Field recorder waveform problem

I've come across a strange problem/bug: when expanding channels to new tracks, some channels show a kind of cycled waveform that doesn't relate to the actual audio (which plays fine). When I zoom in, the actual waveform appears but if I zoom out, it disappears. I've tried to recalculate the waveform overview, I've deleted the wavecache.wfm, I've recycled databases... The problem occurs in PT10.3.9 and 12.3.1
Does anybody have an idea of what might cause that ?

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Field recorder waveform problem