Have outside temps changed? Ac, fans or heaters running more then normal? Can you check or adjust the temp setting easily?
I would at the least double check my temp setting to make sure it wasn't messed with or accidently changed. Then very carefully during a time you can observe the bator over a few hours adjust the temp setting to the correct temp or the adjusted lower temp. Keeping an eye on the overall temp to make sure it doesn't drop to low.
I don't have the same bator, but i did have humidity issues with this last hatch compared to the weather outside. The first hatch temps were cool weather was wet my humidity wanted to stay high except 1 hot dry day my humidity got really low. This hatch it's been warmer and dryer and my humidity was staying really low, so i had to watch it a lot closer for sudden dips.
Honestly, in most cases a few short hours of irregular temps both up or down don't seem to and overall deteramental effect, the hatch rears might be lower but unless it's an extended time it seems most come out ok. I also had my bator unplugged at 1 piont. It could have been unplugged for as long as 12 hours at night. But i still hatched 8 of 15 and a few where infertile to start with.