RT::Extension::Tags : tag not processed if focus is lost before submit

I’m using the RT::Extension::Tags (rt-extension-tags) extension and only recently I noticed that sometimes a newly added tag is “lost”; not processed.

CF defined like this
Type : "Enter multiple tags"
Field values source: “Provide list of values below” (about 30 values)

How to replicate
Load “Basic” page
Click on the CF
Enter a few chars, enough to get a short-list
Arrow down to select one item
Click on the page background (the entry box loses the focus)
Click “Save Changes”

I’ve debugged this behavior and found that the server does not even receive the new tag. Apparently the JavaScript code does not correctly processes this sequence of events.

In at least one case I “lost” the tag even if I hit “enter” or “tab” after selecting the new value. When I do this the tag rendering kicks in. I was not able to catch this case with the debugger.

Note that the UI correctly does not acknowledge the addition of a new tag.
Too bad most of the time the operators don’t pay close attention to the yellow notification box…

Has anybody ever run into this issue?