I believe I've found a solution, I had the same problem. The mobflame particle went away when i copied the world and deleted the old one. Pretty sure this will work on anything on bedrock (I was on ps4 bedrock).
Hmm... I saw bees going into each and every nest. I'll try the experiment again.
I ran some tests with bee nests and bee hives, nine each. None of the hives filled but only two of the nests filled.
I believe I've found a solution, I had the same problem. The mobflame particle went away when i copied the world and deleted the old one. Pretty sure this will work on anything on bedrock (I was on ps4 bedrock).