Line 39 in rc/core/man.kak ends with gk:
But this is run in a WinResize hook, which are run in disposable contexts. Hence the gk does nothing. This makes the cursor stay at the end of the manual after a resize, and makes it very difficult to move the cursor to a good location at all after a window resize.
Yeah, this fails with WinResize, the best would probably be to fix #312 so that piping would detect actual changes to the buffer, hopefully preserving the selection at the correct position.