It seems like the GitHub access token used for retrieving details about this repository from
GitHub became invalid. This might prevent certain types of inspections from being run (in
particular,
everything related to pull requests).
Please ask an admin of your repository to re-new the access token on this website.
The expression return Carbon\Carbon::cr...>matter['update_date']) could also return false which is incompatible with the documented return type Carbon\Carbon|null. Did you maybe forget to handle an error condition?
If the returned type also contains false, it is an indicator that maybe an error condition leading to the specific return statement remains unhandled.