OK! Keep at it and, just so you know, I log in through UsersWP probably 5 or 10 times a day on this or that site and if I EVER see this problem I will try to recreate it myself.
That sounds like a fontawesome version issue.
Please allow us to take a look at the backend by sharing WP Admin credentials.
I will flag your topic for the developers in case they can find a workaround.
We are currently hard at work on some big changes for UsersWP. I know that these are coming soon, so, I will thank you for your patience while we put the finishing touches on some that will be released very soon. I have flagged your request for the developers and they will comment if they have an update.