We have a Umbraco v8 project that has been giving us some trouble.
Whenever we perform a save on a document type that is widely used across our Umbraco, it fails and we cannot perform anything in the backoffice.
We noticed that are queries blocking any other from being run and once we “kill” them, it all comes back to normal - until it happens again.
Yes, we are quite aware of the EOL status of umbraco v8. Unfortunately, we don’t have the client’s permission to upgrade it to v9 and we won’t have until this issue is fixed.