Saving as JPG from PSD doesn't work on my PS even the JPG option was selected - macOS

Saving as JPG from PSD doesn't work on my PS even the JPG option was selected. I can normally "save as JPG" from PSDs without flattening the image before but now it still saves as PSD. Unless you rename the filename or add atleast one character then selecting the JPG option again from the dropdown, or I manually rename the extension from the saved file. Can someone help? Thanks

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