In the last few updates, having shulker boxes in player inventory will cause game to lag when inventory is opened.  New patch 1.10.0 makes game hard freeze for a few seconds when inventory is opened.  When the shulkers are removed from inventory there is still a minor delay, but when shulker boxes are added back, delay resumes.  Attaching video of gameplay.  Win 10 Pro 64 bit.  Realms server.