This does not happen all the time but it is frequent enough to be annoying. I will be working in another application and when I switch windows back to Notes this is what happens
and
The only way to remvoe the numbers is to go to the inbox view and hit the left control key.
Subject: The numbers normally show up when the Alt key is depressed
this helps people to have an alternate way to navigate the UI.
Subject: understood
I understand that the appear by using the alt key - in my case i’m not and i don’t like seeing them 
Subject: Still clicking alt 2 times might make them disappear, too.