HI,
I’m glad somebody noticed this as well. I would like to reinforce this question to the TM developers.
I do a lot of exterior renderings, and I have the same exact issue. interior floors all of a sudden lighten up behind curtain walls. first I suppected issues with the glass material setup or 2sided problem, but it actually happens at curtain position of the sun or hdri image. as a workaround I had to make all my interior floors texture super dark. but it looks perfectly fine in live view. only happens with the exported images.
interestingly enough once I remove the glazing like it’s not there, everything looks fine with the interior. but the brighter export result still the same problem
I tried different setups as above, including adjusting the low to high refinement, suspected on reflection. something just not adding up during export.