I don't know about mushrooms? As far as I understand, they are fine.
Something has had to change for this new behavior. Perhaps crickets from a new vendor? New dusting powder? Different water conditioner?
You said in post #4 "4- temp is slightly above room temp during the day, room temp during night." In my world, slightly above room temp is like 75 F, I'm sorry I mis-understood.
Still, 70 at night is too far a drop from 82, drop should not be so significant. use a UTh on side wall of tank (maybe) at night to just bump the heat up slightly.
You don't want a 12 degree shift in temps, ever. This is very stressful. So difference between day and night temps should be about 7 degrees.
Can I see pics of your other white's?

***Also, you didn't answer in regard to testing for parasites or protozoa...