Not abbreviating one author as et al

In the style guide for one of my manuscript submissions, for citations with more than 10 authors, they want the names of the first 10 authors, followed by the abbreviation et al. for all subsequent authors. I have one reference with 11 authors. For whatever reason, the software wouldn’t abbreviate the last author as et al.
I have that setting fixed in the Output Style for the bibliography Author List section in my Endnote. It should only list the first 10 authors.
My personal workaround is to add a 12th author. The software then abbreviated the last two authors as et al. and they won’t be the wiser. But I shouldn’t have to do that. Does anyone know how to fix this? Or is this just how the software is?

there was a glitch for a while – but the newest updates, I thought fixed it. what Endnote and version are you using? The work around used to be to increase the number by one, I think in your output style.
added in edited comment
but maybe it is still there according to this thread. I do agree with one commenter. Usually the rule is not applied if there is only one more author. Problematic bug/error in EndNote 20.0.1 - Wrong number of authors in some styles

I’m using Endnote 21.2. It’s disappointing that Endnote has been aware of the problem for a number of updates and hasn’t fixed it. Hopefully it gets fixed in the next update.

It is still not fixed. I made a complaint to support services a long time ago, but to no use. The work around doesn’t work.