[Client] Cannot buy Mystery Champion Shard when I should be able to

So, why is that I consistently cannot buy mystery champion shards for quite a while after I have enough IP to do so? I am sitting on 1947 IP, yet the client tells me that I do not have enough IP. Seriously Riot wtf? Can you not do basic Algebra? clearly 19047 > 1700. pls fix.

Update: after much testing i have found that i consistently cannot purchase something that costs 1700 IP until I have 2000 IP. pls fix your algebra Rito.