Illustrator Update 29.6.1 Glitched out a drawing (mac 14.6)

Just updated to newest illustrator and have had a odd glitch appear. Perfectly normal filled shaped suddenly has a pie slice missing from the fill. No reason that I can see in artwork mode and not like any glitch I've ever come across. All paths are closed and no doubled up lines are causing this. Glitch was not there on file yesterday before I updated. Also, opening the file on an older version of Illustrator also shows the glitch. Pretty simple shape and the kind of thing I work with day in and day out in Illustrator and this is an issue I've never seen. Behaves very oddly when moving the anchor points around too (video).