Q: What does it mean if the status changes from Accepted to Required Reviews Completed?

Firstly, congrats that your manuscript was accepted! But we can see there’s a cloud to that silver lining due to this strange status. :-/

Anyhow, the status is probably a kind of glitch or a mistaken update by the Associate Editor (AE) or someone else on the editorial or even the proofing team – because ‘Required Reviews Completed’ is one or two status updates before the Accepted update.

So, you should write to them asking about the status. In fact, you should have written earlier, soon after you got to know of the change from Accepted. Two months is a long time to have been waiting, but it’s ok. So, write to the editor straight away. In case you need help with some email templates for doing so, you may check out this handbook: A practical handbook of templates for communicating with the journal

Hope the situation resolves soon. And again, congrats on the acceptance!