iPad won't download intune MDM profile

On Friday I migrated 60 ipads from lightspeed MDM to intune. I couldnt get LS to release the devices so had to manually erase content and settings of each ipad, i also moved all the devices from LS to Intune in apple school website. If i do a search for the ipad serial number it shows up as being in the intune MDM only. I have also remove the LS MDM entry from school.apple.com

All of the other devices, once completing the reset, automatically downloaded the MDM profile. they were all purchased via a supplier that entered the devices into DEP, with the exception of one device that even though its up to date software (12.1.4) wont take any profile and will continue to setup as a new device.

Trying to add the device through configurator results in the error that the profile isnt valid. even though i can enroll my own ios device via configurator and manage it in intune along side the other ipads. without any error.

I thought that maybe you cant enroll a device via configurator if the device already exists in another group in school.apple.com but it doesnt matter which group i move it to, I still get the profile invalid error when trying to manually enrol the ipad.

Is there something im missing?

any help appreciated.