xbmc/xbmc — comment on commit 4cd482dafd49ec671d5b46077dbef06eeb67ca3b
File:  line 0
By HitcherUK:

Another related bug occurs if the library is updating while XBMC is on the Home screen - the thumb doesn't get set even if one is scraped (I assume it's because it hasn't been scraped at the time as the item gets added to the recently added list).