[CLIENT] Hextech Mastery Shard wasn't issued due to awkward timing.

So on the same game that I reached mastery level 5 with Kha'Zix, I got an S+. So I got the mastery level 5 upgrade animation and the pop-up for obtaining the first mastery level 6 shard, however this was not transferred to my inventory. So from my experience, it seems like the client can't issue a mastery shard on the very game that you reach champion mastery 5, yet it tells you you've got the shard.

How to repeat:

1. Play a champion that is one game away from reaching mastery level 5.
2. Obtain an S- or higher in that game.
3. Observe results.
4. Disappointment.

Any chance of having my mastery level 6 shard back?