Its not about the slots, I think its that the backpack just eats the damned items. I have the items in my pack when I log off, for example. After checking everything. Next time I log on, it all disappears. Every single one. Its strange.
Rocket, when I spawn these days. Several items from my backpack will just disappear for no good reason. I'm not sure if this has been mentioned, could it be fixed? Its somehow quite crippling for a solo survivor like me.