Outpost Vending Machines Broken

This is on both AU and EU Survival.

For the past two wipes, I'll load my inventory with stone to exchange for wood at the outpost. Important to have lots of charcoal with a level 7 quarry... I'll try trading all my stone for wood, like normal, and it will only allow me to trade either 1,500 or 3,000 stone at once. Fine. I'll deal with it. Sadly, only half the transactions go through, though, switching back and forth from 1,500 to 3,000 stone the whole time. On very rare occasions, the machine will allow you to trade ALL your stone for wood, but not very often.