In my signature, it doesn't appear as scratchblocks but as the text itself representing the blocks but without the symbols and stuff. Also, in the page to change your signature it also has the same problem showing.

I think this has something to do with the my stuff glitch

Maybe? Also I have a problem with not being able to see the profile of some users, when I open the profile picture of those images in a new tab it says “Error 503 Backend unavailable, connection timeout”

It also happens with other users's signatures when I see them.

Huh. Could you try to access scratch through a phone that had cellular data and see if that fixes it? (Use cellular data not Wi-Fi)

plus profile comments won't load for me

Both of these bugs have been linked to the My Stuff bug, as shown in the more info section of https://scratch.mit.edu/discuss/topic/756184/