Could you create a "known issues" list
Yes, I agree that's very necessary. Thank you for pointing this out.
In this case, what I'm going to do is to release a new version of the FITS support module where parentheses and other problematic characters will be automatically replaced with underscores. I don't like this kind of 'intrusive' solutions but I think it's the best option to solve this recurring problem once and for all.
Another solution would be hacking CFITSIO, but frankly, I'd prefer to stay as far as possible from that 'thing'. The best solution would be not depending on CFITSIO anymore, but right now I have much better things to do than writing new FITS support code.