I'll just point out that i am quite new to using blender.
I have a vertex group where each vertex has a weight of 1.0, however if i look at the weight paint for that group it seems like some vertices have a different weight than 1.0
(There shouldn't be any yellow/cyan colors only full red (weight 1.0) and full blue(0.0) as far as i know so this is really confusing to me)
I even tried to write a quick python script to print out weights and it indeed showed that a few weights aren't 1.0, then i wrote a script to set all of them to 1 but that issue didn't go away(even tho this time it does print that every single weight is 1.0 in the selected group)
Any advice would be appreciated, if i had to guess then this happens because of some interpolation but what exactly i have no clue.