Hi KJB,
Could you recreate the cell / problematic relation just to varify I have seen this to be helpful in some vendors (when all else fails). is HFR high for all adjacent neighbour or just one.. check its incoming is it bad with all then there might be hardware issue with that cell.
Also get a DT done and try to catch the issue is field try to isolate any specific codec / region / scenario that might be generating the failures.
@ Pix 🙂