This counter counts both aborted frames -- frames prematurely terminated by 8 consecutive '1' bits -- and octet-boundary errors, where a frame didn't land on a clean byte boundary. These are HDLC-layer framing failures most often caused by RF-link bit errors severe enough to corrupt the bit stream mid-frame, so this counter tends to track closely with degraded Eb/No readings rather than with router-internal resource issues. During a rain-fade event that temporarily drops the link's Eb/No, this counter would be expected to spike in lockstep with the signal degradation, then settle back down once the weather clears.