After being AFK at my piglin farm (on my friend's server); I went to the bottom to collect Exp. My Elytra had around 410/432 durability, so I figured that the Exp accumulated after a few hours would give me some levels and repair the Elytra. After I collected the Exp. I found that my Elytra had -51857/432 durability and I did not get any Exp. 

This was on an online server.