When creating a record in a list, first column title disappears and never comes back

We have two or three places in our SKUID app where a user can create a record inline in a list. (contacts, plus two custom objects). When the user does this, as soon as they start typing in the first text field, the first column header disappears entirely - first the text of the header, then a few seconds later the space for the header - so that all of the other column headers “move over” one to the left. It doesn’t affect the actual columns, just the headers. This will stop us from going live (our go-live is planned for three weeks from today) so please help urgently. You already have access to our sandbox and we’re happy to provide more details.