what is a VL?

there are only a few main reasons for over charging and each one has a test.

Sensing voltage at the vr, what is it? IF it is not the same as battery voltage, you have a drop somewhere and it will cause you to over charge.

Bad VR, those can be tested as well. But usually I just rule it in or out based on the other tests.

Internal short to the ALT. Someone posted about this just recently accidently damaging the alt when putting in a screw caused it to over charge.

Intermittent connections to the VR or to the ALT may make it think there is a different voltage than there actually is. BUt again you check voltage readings at each of the fields for the ALT and compare the readings back to make sure they are the same. Either at the VR or the bulkhead or the sensing line as they tap off the same place.

Bad ground is harder, but that I just add a direct ground to be sure.

One of these things is the issue.
Maybe I forgot one but Rapid Robert or someone else will be along to give you other tests.