Based on the location, the image variations are stuck at certain stereotypes

This issue of ethnicity and your geolocation determine to a degree the behind-the-scenes-generated output in Firefly, and this could use more attention. While it isn't difficult to specify ethnicity in people or objects in the scene, it can be counterproductive to have to write prompts to counteract automatic geolocation settings. The prompt is still the main rudder of course in determining output, but to propose building in some sort of 'ethnicity strength' slider that will strengthen your prompts that need to be 'culturally accurate', or to lessen the strength so that it includes more randomness in generating people from different ethnicities.

Now based on these findings, I wonder if Adobe have documented these in their FAQs?

You may be right; I logged out entirely and logged back into my Adobe account, and the hijabs have gone away...

I believe there is some base information carried from generation to generation in the same thread (my terminology). Try going back to the main firefly screen and start a new session.

I didn't use those terms in any of my prompts, but perhaps Firefly includes some of the details from earlier prompts?

Jill, you may have answered the first poster. If part of your description is now stuck with every new generate, so maybe @mellonin typed a prompt sometime earlier that includes a "mosque" or "Muslim" which is affecting every new generate!

I could not get rid of the hijab, not matter what wording I tried: "No hijab", "without hijab", "no headcovering", "no hat".... Those hijabs are stuck on there to stay !

So true. Apparently we need to mention hijab in the prompt.

Interesting. Is it typical for young women to be so modestly dressed? When I initially asked for "middle eastern" people, all of the women were wearing a hijab.

Kind of similar results to yours, Jill