Dear Glen Hodkinson.
Sadly we did not recieve any feedback on the Support Request and therefore cannot offer any troubleshooting or problem solving.
As the issue occurs some time and solves itself after an undefined amount of time i would suggest checking if some external select lists in the store dialog, which were unresolvable at the time of the Import job.
With Best Regards,
Dominik Bittner
Jr. Software Support Specialist