Looking into this - certainly not intended. What platform are you all on?
Edit - We verified that this was happening across the board. Found a server that was rejecting some data calls so we've had a polite chat with it and we reckon that we have a fix live. Sometimes this takes a while to take effect because of the way our servers cache data but we're in the process of validating all of this right now.
Update - The fix has shown us a dramatic decline on the failed data calls. Everything looks to be back in order and we're going to monitor through the night here in Europe. Our engineers are going to give it a deeper look through in the morning to understand what went wrong and see if we need to do anything else with it, but the present belief is that we've stopped the original issue from occuring.
XP is now showing to be correctly applying across TOW, Career, Weapons and Vehicles.