Lion relic sometimes disappears when a paladin holds it idle for a long time

After I forge Holy Fire relic with Lion in FFA, I assign a paladin to it and he chills with my warchief. After some time of being totally idle (say a year or so, talking 803/804 timeframe), when I go to convert I notice my paladin is missing. This happened to me three times now.

First time I assumed someone picked him off while I wasn't paying attention. Second time I left paladin on a totally safe tile, and again I didn't notice he was gone until I converted. There is no way he died from a fight, he was with my warchief who was fine. I couldn't find the relic, and couldn't forge a new one, so was out of luck.

Third time just happened, again in early 804, and I decided to VERY carefully scan my whole territory. It turns out the relic was "dropped" inside of my town hall (not perfectly centered, could see the glow on the edge of the building). I was able to assign a paladin to it, and use the relic as normal.

I moved the paladin a bunch afterwards, and he didn't disappear again.