If memory serves Add-On Updater uses files created by the add-on developers to determine what is the latest version. I seem to remember this occurring once or twice in the past when an add-on itself was updated but there was an oversight about updating the file that Add-On Updater uses to determine what the latest version is.
It would also make sense, at least to me, that if what Add-On Updater sees as the currently installed add-on version number is higher than whatever is indicated as the latest version in the reference file that it would accept that add-on as current, notifying the user that it has done so. I don't know whether it would be possible to trigger an e-mail to the add-on developer if this situation occurs, but that would likely be helpful in resolving this sort of issue promptly as well. Never having seen the code nor programmed in Python, I really don't know whether either one of these things would be a so-called "easy fix" or close to impossible.
Brian - Windows 10 Pro, 64-Bit, Version 20H2, Build 19042
If you think that you can think about a thing, inextricably attached to something else, without thinking of the thing it is attached to, then you have a legal mind.
~ Thomas Reed Powell