Laravel5.6 　unserialize(): Error at offset 0 of 40 bytes

現在2人で制作を行なっていまして、相方とコードを結合したところコンフリクトが起こってしまい、Laravelのcompose.lockの中身をいじりアップデートをしてそのあと開発していて一旦前のファイルに差し替えて php composer.phar update --lockを行なったところタイトルのエラーが出てしまいました。

考えられる原因はパッケージのバージョンをアップデートしてから別のcompose.lockに差し替えてphp composer.phar update --lockを叩いてしまったからではないかと思います。

同じエラーの方々がいたので、参考にしたのですが、治りませんでした。
参考サイト
http://cms.helog.jp/php/unserialize-error/

現在ログ追ってます

[2018-08-10 17:55:31] local.ERROR: unserialize(): Error at offset 0 of 40 bytes {"exception":"[object] (ErrorException(code: 0): unserialize(): Error at offset 0 of 40 bytes at /var/www/vendor/laravel/framework/src/Illuminate/Encryption/Encrypter.php:149)
[stacktrace]
#0 [internal function]: Illuminate\Foundation\Bootstrap\HandleExceptions->handleError(8, 'unserialize(): ...', '/var/www/vendor...', 149, Array)
#1 /var/www/vendor/laravel/framework/src/Illuminate/Encryption/Encrypter.php(149): unserialize('ENCqhl0R2a1s0h8...')
#2 /var/www/vendor/laravel/framework/src/Illuminate/Cookie/Middleware/EncryptCookies.php(95): Illuminate\Encryption\Encrypter->decrypt(Array)
#3 /var/www/vendor/laravel/framework/src/Illuminate/Cookie/Middleware/EncryptCookies.php(76): Illuminate\Cookie\Middleware\EncryptCookies->decryptCookie('eyJpdiI6InlTenF...')
#4 /var/www/vendor/laravel/framework/src/Illuminate/Cookie/Middleware/EncryptCookies.php(59): Illuminate\Cookie\Middleware\EncryptCookies->decrypt(Object(Illuminate\Http\Request))
#5 /var/www/vendor/laravel/framework/src/Illuminate/Pipeline/Pipeline.php(151): Illuminate\Cookie\Middleware\EncryptCookies->handle(Object(Illuminate\Http\Request), Object(Closure))
#6 /var/www/vendor/laravel/framework/src/Illuminate/Routing/Pipeline.php(53): Illuminate\Pipeline\Pipeline->Illuminate\Pipeline\{closure}(Object(Illuminate\Http\Request))
#7 /var/www/vendor/laravel/framework/src/Illuminate/Pipeline/Pipeline.php(104): Illuminate\Routing\Pipeline->Illuminate\Routing\{closure}(Object(Illuminate\Http\Request))
#8 /var/www/vendor/laravel/framework/src/Illuminate/Routing/Router.php(667): Illuminate\Pipeline\Pipeline->then(Object(Closure))
#9 /var/www/vendor/laravel/framework/src/Illuminate/Routing/Router.php(642): Illuminate\Routing\Router->runRouteWithinStack(Object(Illuminate\Routing\Route), Object(Illuminate\Http\Request))
#10 /var/www/vendor/laravel/framework/src/Illuminate/Routing/Router.php(608): Illuminate\Routing\Router->runRoute(Object(Illuminate\Http\Request), Object(Illuminate\Routing\Route))
#11 /var/www/vendor/laravel/framework/src/Illuminate/Routing/Router.php(597): Illuminate\Routing\Router->dispatchToRoute(Object(Illuminate\Http\Request))
#12 /var/www/vendor/laravel/framework/src/Illuminate/Foundation/Http/Kernel.php(176): Illuminate\Routing\Router->dispatch(Object(Illuminate\Http\Request))
#13 /var/www/vendor/laravel/framework/src/Illuminate/Routing/Pipeline.php(30): Illuminate\Foundation\Http\Kernel->Illuminate\Foundation\Http\{closure}(Object(Illuminate\Http\Request))
#14 /var/www/app/Http/Middleware/ForceHttpProtocol.php(23): Illuminate\Routing\Pipeline->Illuminate\Routing\{closure}(Object(Illuminate\Http\Request))
#15 /var/www/vendor/laravel/framework/src/Illuminate/Pipeline/Pipeline.php(151): App\Http\Middleware\ForceHttpProtocol->handle(Object(Illuminate\Http\Request), Object(Closure))
#16 /var/www/vendor/laravel/framework/src/Illuminate/Routing/Pipeline.php(53): Illuminate\Pipeline\Pipeline->Illuminate\Pipeline\{closure}(Object(Illuminate\Http\Request))
#17 /var/www/vendor/fideloper/proxy/src/TrustProxies.php(57): Illuminate\Routing\Pipeline->Illuminate\Routing\{closure}(Object(Illuminate\Http\Request))
#18 /var/www/vendor/laravel/framework/src/Illuminate/Pipeline/Pipeline.php(151): Fideloper\Proxy\TrustProxies->handle(Object(Illuminate\Http\Request), Object(Closure))
#19 /var/www/vendor/laravel/framework/src/Illuminate/Routing/Pipeline.php(53): Illuminate\Pipeline\Pipeline->Illuminate\Pipeline\{closure}(Object(Illuminate\Http\Request))
#20 /var/www/vendor/laravel/framework/src/Illuminate/Foundation/Http/Middleware/TransformsRequest.php(31): Illuminate\Routing\Pipeline->Illuminate\Routing\{closure}(Object(Illuminate\Http\Request))
#21 /var/www/vendor/laravel/framework/src/Illuminate/Pipeline/Pipeline.php(151): Illuminate\Foundation\Http\Middleware\TransformsRequest->handle(Object(Illuminate\Http\Request), Object(Closure))
#22 /var/www/vendor/laravel/framework/src/Illuminate/Routing/Pipeline.php(53): Illuminate\Pipeline\Pipeline->Illuminate\Pipeline\{closure}(Object(Illuminate\Http\Request))
#23 /var/www/vendor/laravel/framework/src/Illuminate/Foundation/Http/Middleware/TransformsRequest.php(31): Illuminate\Routing\Pipeline->Illuminate\Routing\{closure}(Object(Illuminate\Http\Request))
#24 /var/www/vendor/laravel/framework/src/Illuminate/Pipeline/Pipeline.php(151): Illuminate\Foundation\Http\Middleware\TransformsRequest->handle(Object(Illuminate\Http\Request), Object(Closure))
#25 /var/www/vendor/laravel/framework/src/Illuminate/Routing/Pipeline.php(53): Illuminate\Pipeline\Pipeline->Illuminate\Pipeline\{closure}(Object(Illuminate\Http\Request))
#26 /var/www/vendor/laravel/framework/src/Illuminate/Foundation/Http/Middleware/ValidatePostSize.php(27): Illuminate\Routing\Pipeline->Illuminate\Routing\{closure}(Object(Illuminate\Http\Request))
#27 /var/www/vendor/laravel/framework/src/Illuminate/Pipeline/Pipeline.php(151): Illuminate\Foundation\Http\Middleware\ValidatePostSize->handle(Object(Illuminate\Http\Request), Object(Closure))
#28 /var/www/vendor/laravel/framework/src/Illuminate/Routing/Pipeline.php(53): Illuminate\Pipeline\Pipeline->Illuminate\Pipeline\{closure}(Object(Illuminate\Http\Request))
#29 /var/www/vendor/laravel/framework/src/Illuminate/Foundation/Http/Middleware/CheckForMaintenanceMode.php(62): Illuminate\Routing\Pipeline->Illuminate\Routing\{closure}(Object(Illuminate\Http\Request))
#30 /var/www/vendor/laravel/framework/src/Illuminate/Pipeline/Pipeline.php(151): Illuminate\Foundation\Http\Middleware\CheckForMaintenanceMode->handle(Object(Illuminate\Http\Request), Object(Closure))
#31 /var/www/vendor/laravel/framework/src/Illuminate/Routing/Pipeline.php(53): Illuminate\Pipeline\Pipeline->Illuminate\Pipeline\{closure}(Object(Illuminate\Http\Request))
#32 /var/www/vendor/laravel/framework/src/Illuminate/Pipeline/Pipeline.php(104): Illuminate\Routing\Pipeline->Illuminate\Routing\{closure}(Object(Illuminate\Http\Request))
#33 /var/www/vendor/laravel/framework/src/Illuminate/Foundation/Http/Kernel.php(151): Illuminate\Pipeline\Pipeline->then(Object(Closure))
#34 /var/www/vendor/laravel/framework/src/Illuminate/Foundation/Http/Kernel.php(116): Illuminate\Foundation\Http\Kernel->sendRequestThroughRouter(Object(Illuminate\Http\Request))
#35 /var/www/public/index.php(55): Illuminate\Foundation\Http\Kernel->handle(Object(Illuminate\Http\Request))
#36 {main}
"}