Water source flickering in another instance

Title: Water source flickering in another instance
Reproduction Rate: 100% in build #499
Blocker? no, only annoying
Details:
At the end of filling a bucket the water source shortly disappears in other instances (removed + immediately redrawn; looks like a refresh)
Tested with fountain and wishing well.
Build #499.
If you fill a bucket in 2 instances from same source at the exact same time then one will not succeed (when you finish during the refresh).
I would guess its because of shared properties (like a global water stock), but then only the internal properties and not the complete object should be refreshed.