Basically the only reason we trust the Germans over the Kenyans is because of reputation, keep in mind that there is no proof for that statement, we basically take their word for it. But in Germany even recently a stash of 100000 masks was stolen from a local hospital and everyone pretends there is no supply shortage.
So I don't know whether the Kenyans are lying, but I do know that the Germans are, because of information updates I get from local health department connections. Might just be the German government trying to talk themselves out of a bad situation. But right now, we don't know either way.
"We, therefore, wish to inform the public that we are treating this report of alleged disappearance of six million type FFP2 protective masks as fake news & that our cargo section continues with normal operations."
[1] https://twitter.com/KenyaAirports/status/1242455090952384512