Auto Timewarp, editing stills sometimes a frame short.

[ManChicken]

I'm having an issue where I cut a still on my sequence it winds up a frame short.  See attached picture;  the upper half shows my out point marked on the sequence (and I use Exclusive Outs), and the bottom half shows the result after the Overwrite. I selected the 1 frame of the previous clip I was writing over that it left behind - though even if I use the same marks and cut onto an empty track, it's a frame short.

If I undo and mark the out one frame back, it edits to the same (but now correct) frame.  But I can keep doing this, and every couple of frames it ends the clip 1 frame short.

FWIW I am in a 1080p/23.98 sequence, as mentioned cutting a still (with alpha) with Auto Timewarp turned on in the prefs.