I don’t know of any settings that could cause this. I only have two(ish) recommendations.
1) Perform a backup, then restore the iPad using the backup.
2) If your iPad is new, or you have Tech Support through Apple Care, give them a call. They will probably suggest the same thing, but I could be wrong.
2.5) If you are near an Apple Store, call and make an appointment to have them check it out. This is free. They will often fix small software settings problems without charging.
You can use the Apple Support app for the 2’s.