Help please! Something wrong with my indoor Basil

Hi there plant lovers, I’ve been having some issue with my basil plants and I have no idea what it is. The marks look like some kind of pest but I swear I’ve looked all around and couldn’t see anything. It kind of comes in waves, something progressed rapidly and then just stops.

They stay inside by the window and I water them when the leaves start to droop a little bit. Were repotted in the beginning of the summer.

Is this fungal? Could it be the weather change?

I tried cleaning them with diluted hydroperoxide many times but it didn’t change anything.

Thanks in advance for any insight here! 💚