I think it is heat creep. I ran into this a while ago when i brought my printer to the garage. It printed fine in the house, and then when summer rolled around it started to fail. PLA and PETG. I was a random pass, but I finally figured it out. heat creep and when the filiment would do a retraction it would buldge at the nozzel and get jammed up. I can print when the temp drops to about 75-80.

I am in the process of making a machined part to add water cooling. I'll post if it works out well