Venue for imported events do not display

Hi, I am having an identical issue to one reported by someone else on this support request: https://theeventscalendar.com/support/forums/topic/venue-details-not-showing-on-site/

The issue is as follows: We imported a large number of events (along with venues, organizers etc) from another website using the import process described here: https://support.theeventscalendar.com/373241-Using-WordPress-Export-Tools-to-Migrate-Events-Content

Those events themselves show up okay BUT the venues do not display properly. Neither the venue address nor the map shows up. In addition there are some strange irregularities within the WordPress admin when editing one of these imported events, where it almost looks like there are two venues selected, one that is blank and one that is the one we’ve selected. There is also an extra icon that looks like four squares, as seen in the screenshot here https://nimb.ws/qWwIgJ

I have done a full conflict test (no other plugins besides TEC active, using Twenty Nineteen theme) and this did not affect the issue.

If you add a new event all works as expected. It is only imported events that are affected.

I am assuming this is a problem with how they are added to the database during the import process. Any ideas for a solution?

The page I need help with: [log in to see the link]