I just saw this on a thread over in the hatching forum @Beanfox
I personally had terrible luck trying a dry incubation, but other people have had great success
Were you able to find the bill and lift it up so it is through the slit?
I would have waited longer to help since it’s only day 27. But I know that’s not helpful info now.. I have had some that didn’t pip until day 27
Your other egg hasn’t internally pip either?
I sure wish I could help but Call eggs are a mystery to me. I’ve never tried hatching them.
I do wonder if it is backwards again, and that’s why no internal pip. Have you carefully inspected the shell for any bruising which might indicate it is...
Personally I’d probably check it in about 3.5 hours so that you are splitting the time. But I might be too paranoid and chances are it will be fine overnight. Maybe take off the plastic overnight and just keep humidity around 70% in case it manages to get in trouble with the plastic?