I have seen this issue before at Mr. Excel. No idea why it happens, and it happens to me since my version of Access was updated after my laptop went bye-bye. The only solution I had was to copy the sql, open a new query and paste it in.
EDIT - tried something seeing as how I now experience the issue. Cancel the prompt then Ctrl+V will paste a new query. Of course you will get the Save As prompt.
The more we hear silence, the more we begin to think about our value in this universe.
Paraphrase of Professor Brian Cox.