The screen capture indicates code violations/errors coming from the T1 XT side into the MX2820 only. You mention monitoring for these errors at a DSX jack and not seeing these errors. Without knowing the exact relationship of your DSX jacks to the circuit I can't definitively comment why you're not seeing the errors testing from them. However it is possible the error condtion is occuring between your monitor point and the MX2820 backplane DS1 back plane connector for this particular STS-1.
To isolate the source of the issue I suggest you intrusively test the circuit from the DSX 1 appearance facing the MX2820 with a TBIRD or any other T1 BERT set towards either a Digital Line/Net loopback or Codec Line/Net loopback (software loopbacks placed on the port that loops the circuit both directions at different places on the STS-1 Module). Assuming you see errors on both of these test, I'd suggest performing a protections switch to the redundant STS-1 module if so equiipped. If not I suggest you secure a spare STS-1 module for the redundant slot and try a protection switch. If this doesn't resolve the issue then we will have to focus our attention to the backplane/cable to the DSX 1 appearance for physical trouble i.e. poorly terminated conductor defective DSX 1 jack contact, etc, etc.
Hope this information helps sir!