Other mistake: When Batman is video calling the Riddler and passes the phone over to the D/A, you can see Batman's face still looking at the phone in the reflection of the Riddler's glasses.
Other mistake: Miles explains the presence of the white bracelets that the Efficient Man slapped on their wrists as biorhythm monitors that act as keys for their room, each assigned to a chakra. Blanc's presence was not expected or announced, but not only Ethan Hawke had an unexplained spare bracelet, but he is also assigned a room, when there are 7 chakras and he brings the guest count to 8. It should also be noted that supposedly they are the "key" to each room, and yet Andi comes and goes from them as it pleases her (ironically the very sort of mistake that birthed the term "Fridge logic") and nobody wears them for the rest of the movie at all because the gag ran its course.
Other mistake: In the origin story of Poirot's facial hair, we see the damage on his cheek is massive, well into the cheekbone. His girlfriend says he'll grow a moustache to cover it, and surprisingly, it works - nevermind the fact that scar tissue wouldn't grow hair. When we see the scar without the moustache, while smaller than the initial damage, it still extends into the cheek at the level of the nostrils in a way that the 'stache couldn't seamlessly cover like in the rest of the movie and its prequel.
Other mistake: Richie, with a bullet hole through his right side, arrived at Leonard's and thrashed about on the table while his wound was being stitched. He was even turned over so that Leonard could stitch the back side (exit wound). Richie's hair became somewhat disheveled during the procedure, but after he recovered and walked into the other room, his hair was neatly combed/styled and his suit/tie showed no wrinkling or signs of blood on them (unlike his shirt around the wound). (00:22:00 - 00:33:55)
Other mistake: It didn't make sense Catherine was a Catholic preacher but worked at The First Baptist [Protestant] Community Church" and drove a van with the same on it. (00:31:00)
Other mistake: It didn't make sense that the "fighters" were given protective gear (vests, boots, arm and elbow pads, etc.) if death was an expected outcome. Also, a private "for profit" prison is paid per number of inmates housed, so deaths in The Dungeon would reduce profits and would be avoided, not encouraged. (00:34:00)
Other mistake: Connor told his newly-pregnant wife Candace, "So you need to eat twice as much, baby, 'cause you gotta feed the baby now." Maybe this was meant to be humorous, but Connor had just said he reads (meaning knows things) and suggested Candace eat an avocado a day. In general, the first (and even second) trimester of pregnancy does not require ANY extra calories. (00:27:05)
Other mistake: It had been (acid) raining for some time and a puddle along the curb was shown with brown (Fall) leaves in it. If the acid rain was dangerous enough to eat away human flesh, it should have been powerful enough to erode/destroy the fallen leaves soaking in the puddle full of acid rain. (01:02:10)
Other mistake: The white horse looked very uncomfortable from what appeared to be an improperly placed bit (too far back and/or misaligned in its mouth). The handler should have noticed something was wrong and intervened. (00:20:30)
Other mistake: The close-up of wine being poured into the glass shows that after reaching about two-thirds full, wine continues to be poured into the glass without increasing its level. (00:04:40)