General mob spawning (passive and aggressive mobs) has drastically reduced.
while unsuccessfully looking for endermen in overworld noticed other mobs were not spawning as usual (prior to update). I ended up purchasing ender pearls to open end portal.
Once in the end I spent about an hour running around and only found 4 endermen.
Related issues
Comments

Thank you for your report!
However, this issue is a Duplicate of MCPE-21856.
If you would like to add a vote and any extra information to the main ticket it would be appreciated.
If you haven't already, you might like to make use of the search feature to see if the issue has already been mentioned.
Quick Links:
📓 Issue Guidelines – 💬 Community Support – 📧 Customer Support – 📖 Game Wiki
this appears to be a mob cap issue, killed off chicken farm and mobs started spawning again. it appears that my base which has farms & trading hall takes up the entire mob cap. (it did not prior to this release).
Note: I do not consider this base to be huge and it is not laggy at all even on kids ipads with 5 players in world)
so when anyone is at the base we can go anywhere in the world, nether and the with no spawns appearing.