Make sure "Key Pickup" is enabled in the client, and your "Move only" skill is not on Left Mouse Button.
Otherwise, with the default filters, the bot should not typically loot useless items, but it's something that can happen in this game due to how looting works. For example, the bot has to press the Key Pickup key, hoover over the item's label, and click once. If another click action takes place while the client thinks the previous key is still held, it'll pickup whatever item is under the cursor as well.
