Try duplicating the file so you have your Layered version safe then stamp the Layers ontop by pressing Shift+Option+Cmd+d to plut the artwork on one Layer on top.
This is not a new issue and occured because the gradient in a gradient fill layer applied across all artboards. So when you added a new artboard (e.g. by duplicating) then the gradient start and finish points were changed.
It was supposedly fixed in 2022 but it does look like that old issue is back in the current version - I can confirm it in v 24.1.1 on Windows 11 v 22H2
Hello @CoryShubert , Its been a week, my work is pending due to this issue even after providing the file, this is very disappointing. Please look into this ASAP.