ItemShops bug where items get duplicated (ItemShops 1.6.2.2 - PaperMC 1.21.8)

Hi, i recently installed Itemshops in my PaperMC server as it fits perfectly with what we want, but upon testing it, we have seen that the items in a shop's chest do not get removed after someone buying them, thus duplicating them. Anybody know why this might be happening, or knows how to fix it? I can provide config files, this is my plugin list: