Thank you for getting back to me, @ultimatemembersupport
I am using Version 2.0.25
I do not have any security plugins installed and did a conflict test as instructed. While all plugins were disabled, with the exception of Ultimate Member, and the theme set to default, I still experienced this issue.
I have tried deleting and reinstalling Ultimate member, although it comes back with all its data still so this may not be helpful. I have also tried changing the meta of the password field and that does not make any difference. It seems to just not be storing the password for the users, but it is saving other data from the form.