I noticed this when both using the SELFIE camera as well as when operating a vehicle during one of the Legion invasion events. Whenever the normal action bars are replaced by the vehicle action bar, the key bind text is missing. I disable Dominos and reload, and the text is visible. Whenever I reenable Dominos the text is missing again. So it defintely seems like its something to do with Dominos.

Four years later I verified this is no longer happening