I went 3,000 tiles away from where I usually adventure and was able to finally find bees and their nests in my realm. It appears that you have to go to chunks that have never been loaded...
My understanding is that realms run on the latest version and that's why they don't provide an option to update to the next version (it's automatic). Plus, my launcher says I'm running 1.15.1
I have a realm that was generated several updates ago. I have the newest update and have gone to several plains biomes and seen hundreds of trees, but no bees or beehives. I went really far and checked chunks that I've never been to. Once again, still no bees.
I am experiencing this problem. Doesn't appear to be fixed.