On my PlayerRespawnEvent, I have items given to the player. However, the items merely only appear in the inventory. When I try to interact with the items (right click), they disappear without a trace. Did anyone have any issues similar to mine, and if so, what did you do to overcome it? I really don't want to use a runnable... EDIT: I am calling Player#updateInventory() as well.
Try doing it with a runnable as AleWu said. Can't remember correctly, but I've had similar issues like this in the past and managed to fixed them through delayed schedulers.