This occurs for me on a regular basis but I can't actually nail down the specific cause. With building our base I've been doing a lot of crafting of parts. After a buddy complained about how low crafting xp was (and then the thread here) I decided to up our server to 2x crafting.
After that change I started the building of our base and was watching my xp to get a rough idea of how much various things were giving it. It would seem like quite often when I used the craft 10 or craft XXX (all) buttons that I would stop getting xp for them. I'd exit menu's, go back in, etc no change. However if I clear the crafting queue and restart it, then it sometimes works again. Also when I craft a single item at a time it always works.
Something definitely is wrong though. I've watched it go through 30 foundations and not a single ticket of xp EXCEPT the 'over time' trickle of xp.
Anyone else notice this? Can other builders out there please assist in watching as you mass craft stuff to see if you also see it. It would be nice to know if this is a just me kind of problem or an actual widespread bug.