The mod Fluid Must Flow caused a non-recoverable error.
Please report this error to the mod author.

Error while running event FluidMustFlow::on_built_entity (ID 6)
FluidMustFlow/linver-lib/entity-utils.lua:21: attempt to index local 'neighbour' (a userdata value)
stack traceback:
FluidMustFlow/linver-lib/entity-utils.lua:21: in function 'getConnectedNeighbours'
FluidMustFlow/control.lua:66: in function 'ductConnectionsControlEvent'
FluidMustFlow/control.lua:416: in function <FluidMustFlow/control.lua:411>

Could u give me more information? About what version of factorio are u using and what other mods are installed? Thank u in advice

Hello, I get the same error.

I'm playing on the latest version of everything with full angel + bob as only major mods. Bob's burning heat sources are reactor like buildings with this neighbor bonus mechanic.

In the moment when you place two buildings with fluid as power source next to each other this error occurs.

Greetings

It was SeaBlock pack 3.7
https://forums.factorio.com/viewtopic.php?f=190&t=43759
Along with Fill4Me 0.7.1 and SqueakThrough 1.3.0

It would crash when adding an oil burning heatsource next to an already existing one.