There were changes from Laravel 5.6 to 5.7 that might have caused this:
From the Upgrade Notes:
A new data directory has been added to storage/framework/cache. You should create this directory in your own application:
mkdir -p storage/framework/cache/data
Then, add a .gitignore file to the newly created data directory:
cp storage/framework/cache/.gitignore storage/framework/cache/data/.gitignore
Finally, ensure that the storage/framework/cache/.gitignore file is updated as follows:
*
!data/
!.gitignore
There was also a change from Laravel 5.5 to 5.6, but from what it looks like this seems unlikely to be the cause.