After the Winter 21 update I've come across an issue in a clients environment where when entering a negative value into an apex input field returns an invalid number error. The debug log prints '|VF_PAGE_MESSAGE|Invalid number', and once the output panel is reRendered it looks as though the negative symbol has been changed. (See below images). This behaviour was not occuring previous to the Winter 21 update.
I am unable to reproduce this issue in our development environment, it seems as though it is a local issue with their specific org.
My guess is that upon reRender the value is being converted into a string and so is not being recognized as a valid integer, although this seems unlikely that this would have been a change included in the update.
Any insight or tips would be greatly appreciated!