How long does it take for an 8 bit PIC to stabilize after Power-up?

[Art]

That’s an interesting find.
You could probably cycle the calibration value at run time then.

for value = mincalvalue to maxcalvalue
calvalue = value
turn led on
pause
turn led off
pause
next value

You could probably calibrate it yourself with a good freq counter,
and double check their work or what they thought was operating temperature.