I have only observed this once, which could mean it was a fluke, but it seems a tad buggish.
1. An addon Updater window automatically appeared at some point, showing an update for Win Ten App Essentials.
2. Right before noticing that, I turned off my laptop WiFI (hotkey), thinking I was actually turning it on.
3. Then I hit "Update" to install the update.
4. Since there was now no internet access, I got an error dialog, saying that it couldn't update.
5. Once I turned WiFI back on, I ran the NVDA->Tools->Check for addon updates.
6. It reported "No addon update available". That is what I consider the bug: it "forgot" that there was an update it had just told me about, because it was unable to download it.
(N.B. should probably say "No addon updates available".)
7. I restarted NVDA, ran step 5 again, and got the usual update dialog, which allowed me to update W10AE.