I was actually just parroting claims of message arrival time/sync inconsistencies in this thread. I don't use the app too much, in part because nearly everyone I know uses Skype instead of Discord, but I've never personally experienced a bug.

My personal biggest gripe is the lack of easy searching. I rely on it a lot, and Skype usually does an okay job at it (even though it can often be slow and tends to lag the UI).