I heard about problems with backpack size before. Happened on the last patch, therefore it wasn't a problem. Maybe the devs fixed it.
Have you tried to set it to 28 or 29. Maybe it was reset because you've choosen a high number.
I'm not sure I understand your first paragraph.
In BL1 the backpack under normal play could get as high as 40-50+, so a limit in the high 20s is much too low for BL2, if that's what Gearbox is intending with this latest update.
Here I am almost finished with TVHM, I have a backpack with 401 weapons and items, and I have to dump/sell all but 26 in order to pick up another weapon or item? Ridiculous, Gearbox!
There must have been another update from steam...my editor crashing the game again. Anyone else experiencing this yet?
Yes, they just updated it again, today.