I was in the process of writing a long reply when your post made me try:
turn OFF remove dupe frames in L&T. FCP brings file in as 59.94 (you can see dupe frames in this file (real, dupe, real, dupe, dupe….repeat). When I drop that into a 23.98 timeline FCP magically skips the dupe frames and it looks good!
I was also going to try and bring the 59.94 file onto a timeline and manually edit out the dupe frames. But looks like FCP figured it out. L&T has a bug in there somewhere.