So, can anyone tell me why this is happening? have never encountered this before

So the problem is that of some reason some parts of the model wont go noncollidable. i got a script wich sets all the baseparts to collidable = false(you can see the script in the end of the video.)

the model is made up by joints and constraint welds, details being welded to the corresponding joint part.

https://gyazo.com/f20191b2057c02c070b176374e552ee1

Appriciate any help;)

:The welds could be messing with your script, I would suggest just going inside the properties tab for each part and setting the collidable feature to false rather than doing it through a script.