Upper case letters that stay upper case no matter what I do
On my iPad I sometimes inadvertently type an upper case letter and, having done so, can never make it become lower case. I can delete it and type the letter again in lower case but it once again comes out as upper case. The only solution is to type the letter twice, then delete the upper case version. I assume there's something in SETTINGS that is causing this but can't work out where it is. Any suggestions?
iPad Air, iOS 9.1