From my testing and what others have said this appears to be solely a physical button issue, and seemingly may be somewhat device-specific as well. Within RA itself, it definitely looks to solely be an input timing issue in RA’s Android input driver, with the RA cores being completely separate from this.
Any games that may happen to have looser timing requirements for simultaneous presses (i.e., two separate presses within, say, 3 frames - i.e., 50 ms of one another being treated as simultaneous) may work relatively OK with this issue present anyway but of course many games didn’t do that since that necessarily creates slight input lag. Given that fighting and brawler games (where extremely responsive controls are needed) are among the most common for such button combinations, it’s not surprising that most of them are very demanding in needing you to press all buttons at exactly the same time.