I have this problem where if I sell items to traders like hundreds of purified waters at a time it glitches the traders out where they sometimes take my water and don't pay me for it. So I end up spending money without getting any caps in return and the only way to fix it is by restarting the entire game. Wtf is this?

Just curious, how could you sell hundreds of purified waters to traders? I think at minimum that would be 600 caps for 100 water, and I've never met a trader who had that many caps unless I'd bought a lot from him...

Are these traders that work at your stores? because these settlers will sell things they pick up to meet their needs. They still need water, food, amo, etc to meet their needs.

I noticed before I had stores, I gave NPCs weapons, ammo, etc. And when I posted them at my stores, they decided to sell what I gave them. I gave one guy a shotgun, and he decided to sell it and I noticed he replaced it with a pipe rifle in his inventory. I gave my armorer a clean blue suit (because I like my traders to look nice) he decided to use a cage armor that was stocked in his store.

If these are settlers that you turned into traders for your stores, they will pick what meets their needs first and then sell the rest. which means they may steal your stuff and sell it back to you.

@neildarkstar if you use cap collector and invest 500 caps in their store, and they are the level 3 or level 4 trader, they have more caps in their inventory.

No it's Trashcan Carla, the Drumlin Diner and Graygarden traders. I give them enough water to take their caps to almost 0, and that's how I get profit. Also I buy things from these traders which is why I sell hundreds. I buy shipments from traders and then sell hundreds of water to get my money back. But the thing is, after I trade too many times apparently they take my water but their caps stay at a set amount. First time it happened was at the Graygarden trader, it was stuck at 40 caps. He would take my water but wouldn't give me any more caps. Then Trashcan Carla had 600 caps from me buying from her, and I sold her water only for it to stay at 600 but I'd lose water. If I restart my game it'll work perfectly fine though.