instagram app shutting down

Handed my old iPhone 6s down to my daughter. Phone is in perfect condition, working well. Backed up her old iPhone 5 to iTunes first. Then reset her new (my old) 6s by 'Erasing all content and settings'. Then restored her recent backup onto the new phone.

This all went well. Have done it many times before. All data was restored as expected, photos, music, Apps etc.

The Phone then Updated all Apps. I downloaded and installed latest iOS 11.4.1 (15G77).

All Apps and phone functions are working perfectly.

I have one perplexing problem.

Instagram App crashes soon after login. You see her Instagram home page for a few seconds then it blacks out and returns to phones home screen.

• The App only has a problem with my daughters specific instagram account.
• I can log into the App with any other account and use it successfully on the phone.
• She can log into her account on any other phone or device.
• She can log in thru safari on the phone but when you try and transfer to the App it shuts down.

I have tried the following:

• Uninstalled and reinstalled App many many times.
• 'soft' reboot. i.e.: turned off/on.
• 'Hard' reboot
• All software is latest up to date.
• Her Instagram account works fine on another 6s we own running same latest iOS 11.4.1
• We have logged out of all her accounts and devices by changing password. No joy.

This seems to be a specific problem that this specific device has only with this specific instagram account!! Bizarre!!

Only thing I can think left to try is Re-Erase phone and Re-restore.

Any thoughts?