I think Canawhatsis is on the right track.

The buffering in (most) potting mixes lasts about 2 months or so, and she does look too big for her pot. Likely it's time to transplant. You might even consider another root trim, but only as a last resport. (if no larger pot is available)

Did you repeat the mite spray about a week after the first? Any egg cases not killed with the initial spray will sill hatch, and the damage can continue. Be sure to rinse-off the spray after treatments. (the next day should be fine)

Once you take 'em outside, I'd make sure the plants are not in a depression (or 'bowl') so the excess rainwater won't flow twords the plant, but away from it. Perhaps a rock-lined hole, but keep the plant in a 15 gallon pot. (half-buried in the rock-lined hole)

Sure hope you find a nice quiet spot this time. It was heartbreaking watching your plight last summer.