That all depends on the calls that MrP's code uses after it's updated SQL data.
Unfortunately, I do not have the set up you have, nor time to implement, and would require that any testing be done without any SQL modifications you've made.
Do you get any console errors, server console or otherwise?
I'd really be curious if this happened without any SQL addons, as it sounds like a hook or other function is grabbing xgui input and not letting go and allowing XGUI client side (or server) refresh.
I know you stated 'this was happening before' you went SQL, but, honestly, I do know that XGUI sometimes did that, and was fixed some time ago.
Have you tried removing all addons but ULib and XGUI, and added one or two back at a time?
And what gamemode? DarkRP?