I'm disappointed by the "Me too" button in this forum

When I encounter a topic in this forum and click the up-arrow button, I see the number increase by 1. Clicking the button again, removes my "up 1" vote. The action of that button is clear.

The "Me too" button is less clear. When I first see the button, it typically shows a count. But when I click the button, the count disappears. Clicking the button again brings back the count.

Experimenting revealed that when I first encounter the buttons on a new topic, the up-arrow and hand are outlines. Clicking either button fills in the outline, which I interpret as recording my vote.

What's puzzling is why the "Me too" button does not retain the count when clicked.