A duplicate frame on import

I have a quicktime reference file from Avid Media Composer, which somehow has generated a single duplicate frame on import in Davinci Resolve. When I step through the file frame by frame I can see on the burned in timecode, duplicates 1 frame a random place in the film.

When I look at the same file in Quicktime player it doesn't show the duplicate frame on the exact same place.

Davinci has added 1 frame a random place in the film and the file has an offset from that point.

Has anybody seen this problem before?