I have a document with a few two-column text frames. On the left pages of two double spreads, the column resizing double arrow mouse cursor appears in the wrong spot, either two the left or to the right of the column gutter. On the right pages of the spreads, the hotspot is centered on the right column gutter guide (rather than the center of the gutter as one would expect).
The feature can still be used since the offset remains constant if the user clicks and drags. One just has to find the right spot inside the text where the phantom handle appears. In that area, clicking to place the text caret is not possible since the column resize behaviour "steals" the mouse events.
I have not tested if this is related to that particular document or not, but just in case, I have made a copy of the file where I encountered the bug that I can provide staff with if the issue cannot be reproduced otherwise.