This seems similar to: 'Archive' and 'Mark as Spam' buttons change locations unexpectedly
I did not encounter this, as I do not have GMail & Non-GMail e-mails in my inboxes. Could you provide an order of the buttons / button groups that would be optimal? It seems that at least the following buttons appear based on the e-mail (account) type and can change the position of the other buttons:
- GMail Labels
- “Remind Me” Bell