I am with Hosting.com (formerly A2Hosting), and I’m on a shared server environment (not a VPS), so they can’t roll me back to a previous version or downgrade HTTP without impacting the whole environment. They confirmed they are running LiteSpeed 6.3.6, and the problem persists on the two dozen sites I have running on ModX. At this point, their tech support is (predictably) calling this a ModX issue that requires a patch to the CMS.
Just to follow-up on this, they confirmed they have Build 5 installed, but refused to patch it to Build 6 on-the-fly just because one customer requested it. I can respect that, but if anyone is using A2Hosting (now Hosting.com), just be aware of it. They didn’t say when they planned to patch it, so I’ll limp along with the plugin, which works pretty well.