When I am scrolling down the leaderboard of the monthly event the list sometimes just suddenly jumps back to the top. This has happened repeatedly. It usually happens the first time when I reach about ranks 20-30. Sometimes it happens several times before I am able to scroll to the bottom.
First I thought it might be to short disconnects, but it also happened at home where I have a stable connection.
Here is a video of it, you can see it once at the beginning and towards the end a second time:
Phone used: Xiaomi Mi 10T Pro