The answer to 'why is my skylight curling shingles' is that the shingles around the skylight are curling due to excessive heat buildup and exposure to UV rays. This can happen when the skylight is not properly sealed or flashed, allowing heat and moisture to get underneath the shingles and cause them to curl up at the edges.
Curling shingles around a skylight is a common problem that can lead to leaks and further roof damage if not addressed. The good news is that it's usually a straightforward fix, though you may want to call in a professional roofer depending on the extent of the issue.