No grade showing after match

So I'm trying to get some mastery progress with certain champions and noticed that this has happened a couple of times now. So after a match, in the end result 'lobby', there's no grade being shown. This is really annoying, especially when I'm doing well and then just don't get any mastery points nor a grade that could provide me with a mastery chest. Does anybody else experience this bug? And does anybody know if Riot is working on fixing it? (Ps: I reported it, but I'm not sure if Rito took note of it)