Since many versions I see the same behavior, and I understand it as an issue :
1. I create a new profile in "Access rights" -> "Profiles" (eg, a purchaser : they are user & contact but not resources and they have limited access rights)
2. I set everything I want for those profiles without any problem
3. I change the profile for a brand new user, everything works properly
4. I try to allocate the user to a project : the pop-up looks fine (I can see the new profile), but when I click OK I get an error message "Invalid Controls" "You don't have rights to create this item" ... but I am administrator-god-all-mighty?
To be perfectly honest, I have got a very dirty workaround: I create the allocation with an accepted profile ... and then I directly modify it into the database. I know it's bad, but it works for several version now 😉 (at least since something like 6.2.x or approaching)
Check sort order for new profile and don't keep it to zero.
Order of profiles is important as you can not allocation resource with profile having sortOrder < to sortOrder of your own profile.
It works, many thanks.
The sort order was not empty, but with lower value than administrator.