Amount of interlacing differing between captures?

I'd imagine that this question has already been asked/answered, but there are so many threads about interlacing that it makes it very difficult to find this specific issue.

I've been capturing old basketball games from (NTSC) VHS tapes for the past few weeks, all of which come across as interlaced of course. The most recent game I've captured, however, seems much more interlaced than the others. In other words, the horizontal comb lines are much longer on this video than on the other videos that I've captured with the same equipment.

The end result of this is that after applying deinterlace filters in virtualdub, the finished video looks blurry. It doesn't look interlaced anymore, but it looks like there's ghosting or double-image blurring on movement scenes.

I've captured it at 29.97 fps just like all of my other captures that don't have this problem (to this degree). Is there anything I can do to reduce this? Would recapturing at a higher frame rate make any difference?

Thanks in advance.