Appreciate the speedy fixes! Thank you once again.
I'll see if I can test the i-frame thing in depth later on.
To be fair, it was something I noticed in passing but didn't really look into it.
Quick Edit: The i-frame thing happens when your character's colour is set to anything other than 'none'.
(Also you only flicker if you touch a spike, if you get hit by an enemy's melee attack, you don't flicker at all, but you're still invincible for a bit.)