This error only happens in champion select. Nothing specific seems to trigger it, and it doesn't kick me out of the champ select even though my client freezes/crashes. When reopening the client it needs to load for 30-60 seconds, which unless I've locked my champion usually kicks me out of champ select.
Are there any known fixes for this kind of issue? My friend also gets the same error so I assumed it's not that rare and there would be a couple of threads on this but the only ones I've found don't offer any decisive solution.