I am aware of this glitch and have been working to correct it, In the mean time to update character bio have your players
1) Write up the bio in note pad.
2) Make sure cookies are enabled
3) Pull up character sheet, click edit.
4) In the dropdown box remove DST (select the blank option), save. (This will remove the character sheet from the page, THEY WILL NOT LOSE ANY CHARACTER INFORMATION.)
5) Go back to the edit character page reselect the Pathfinder Character Sheet template (all their information will still be there) copy/paste new bio, save.
I've done this multiple times and haven't lost character information. The character information is saved as temporary files so it is very important to have cookies enabled. They might want to do a test run before to make sure it'll go smoothly.
One last thing while some people like yourself and I are having these issues other people I've talked to are not. I believe they may be browser or OS related, If you could tell me what browser and OS they have been using it would go a long way into getting a permanent solution in place.