8x scope on sv98 going between regular and thermal

Yeah, that’s a known bug going around right now like many other annoying ones. A few scopes and sights will randomly turn into thermal mid-match for no reason. It’s not just you  happens across different optics, sometimes even the basic red dot ones. Seems totally random, sometimes after respawning or swapping loadouts.
It’s been reported a few times on Reddit and the forums, so you’re definitely not the only one seeing it. Hopefully DICE patches it soon because it can actually mess with visibility and gameplay when it triggers.