List bug on my main watchlist

After I was trying to move some items on my main list (https://www.imdb.com/user/ur35710718/watchlist?ref_=nv_usr_wl_all_0) multiple bugs occured: screenshots below - I have multiple shows at #1 or #2, then a few gaps on items #128-#140, and I see items #482-483 even though I should only have 481 on the list.