InDesign text wrap buggy; changes when grouping or other irrelevant changes

Two items are on a page over a text frame. Both items have the same text wrap setting. If I group the two items together, it shouldn't effect the text flow beneathe, and yet it does.

Also, if I move one of the text boxes or change it's text wrap setting by one point, the text reflows, which is to be expected. But when I change the text flow setting back by that one point, or move it back manually by that one point, the text wrap DOESN'T CHANGE BACK. It only does that when I use undo to set things back.

What crazy setting am I missing here? It seems like grouping or moving a text box is performing some other unseen function that I can't change back manually, but can only fix with undo. Anybody else have this happen?