Stuck while splitting stacks with exact number

I haven't seen anyone else have this problem but this is what  happens to me. EX:

Open up backpack.

Click on wood to split. 

Click on the number to input a number exactly (say 750 exact)

Press Enter

Backpack goes away and I am now frozen in place. I  can only look around but cannot move or open anything up.

Figured out the problem