Frostfang/Remnant of the Watchers Fails to Stack or Upgrade

For some unknown reason Frostfang/Remnant of the Watchers / fails to continue stacking past 479/500. For two games in a row while playing Zyra, the item ceased to gain stacks and therefore wouldn't upgrade to the completed version. This meant that I couldn't place any wards. This is making the game unplayable as a support mage. I'm unsure what could cause this, only that it began happening today. If this is some April Fools joke on Supports, could it please stop.