As you place a block such as sand, or gravel on the side of a block with water below it I drop frop 200 FPS to around 10 FPS.
MC-134109
Frame rate lag when placing blocks with gravity in water!
Resolved
Awaiting Response
1
(Unassigned)
Unconfirmed
FramerateDrop, framebuffer, gravity, gravityblock, lag, water
Minecraft 1.13
Retrieved
Please check if that's still an issue for you in 1.13.1.