I took this up myself. I did some investigating, found the issue in the source, and found a solution. Here is the text of my response to Hyland Support. The context is getting Jetty updated, so the versions are in reference to Jetty:
I got a workaround to well...work. I tried v9.4.x to no avail, as there are too many changes with configuration. I at first, thought I needed to backport something from v9.4.x to v9.3.x. However, after looking at the Jetty source, I found that the fix made its way into v9.3.x. It made it with the following commit: https://github.com/eclipse/jetty.project/commit/b0fc078a1c795f8c1704a57fe5f6c49922348488
So I cloned the project, checked out the v9.3.30.v20211001 tag, performed a Maven build, copied up the jetty-distribution ZIP into the solr/server directory and unpacked it. I backed up 'lib' and 'start.jar' and effectively replaced them with the files from the new build. The new build had additional files, but I only copied the ones that already existed in the ASIE/Solr distribution. And I copied the non-Jetty files from the old 'lib' to the new one (metrics, javax).
It all appears to be working right now.