History in Messages for a single contact shows the last week or so, then skips to 2016

I have one contact in my phone with a significant history. I do not have any retention limit set on it and I don't want to have to purge any of the history if possible.

It will typically show messages from the last 5 days or so. Then it skips to the same message in 2016 and shows all the history after that point. Forcing a sync with iCloud will typically resolve the issue temporarily. but it reverts later on.

This happens on all of my devices, Mac, iPhone and iPad.

How can I fix this so the history shows up consistently?