I placed a villager and a work station (composter). In a well lit, secluded area. I went about 100 blocks away, and I returned to find the composter, and the villager had disappeared. This has happened twice within a 15-hour timespan now.  I am on a realms server, but I have been the only individual on within this time span. I am running Optifine version 1.16.4. 

I have included a before and after of this, including a timestamp in the bottom right corner.