Happy to provide archived server saves upon request.
UPDATE: starting from scratch with a fresh livonia server and the same mods has, over time, lead to reproducing the bug with narrower constraints under ticket T188875, which helps narrow down the cause as well as verify that it will happen with any server in this situation on an ongoing basis rather than just ones trying to persist save files from previous versions.
Also, ticket T188874 may also be tangentially related.