Two malfunctions from the same magazine...both caused by the same problem. Weak spring.
One is known as jumping the lips. Weak spring is the most likely culprit. The lack of a speed bump on the follower is a player. Most often happens on the last round, but can happen on the next to last round...jumping clear of the gun...with the last round chambering normally. If you've ever found live rounds among your brass...Heeeere's yer sign.
The other is called Bolt-Over Base misfeed. Same problem. Overspringing the slide is often a contributor, but rarely the sole cause if the mag spring is up to snuff. What happens is that the slide literally outruns the magazine and the cartridge isn't fully seated in the feeding position. Breechface rail catches the case in the extractor groove. Base goes down...Nose goes up.
The 1911? Well...It ain't exactly a Swiss watch.