using bobsmods i often get "fluid mismatch" spams and unnecessary clamps when trying to connect gaspipes (ie hydrogenchloride) with each other.
Trying to unclamp them leads to lua errors

22788.480 Script @Fill4Me/stdlib/event/event.lua:153: LuaEntity API call when LuaEntity was invalid.
stack traceback:
Fill4Me/fill4me/fill4me.lua:87: in function 'func'
Fill4Me/lib/event_extend.lua:84: in function <Fill4Me/lib/event_extend.lua:76>
[C]: in function 'pcall'
Fill4Me/stdlib/event/event.lua:148: in function <Fill4Me/stdlib/event/event.lua:127>
22789.229 Script @Fill4Me/stdlib/event/event.lua:153: LuaEntity API call when LuaEntity was invalid.
stack traceback:
Fill4Me/fill4me/fill4me.lua:87: in function 'func'
Fill4Me/lib/event_extend.lua:84: in function <Fill4Me/lib/event_extend.lua:76>
[C]: in function 'pcall'
Fill4Me/stdlib/event/event.lua:148: in function <Fill4Me/stdlib/event/event.lua:127>
22814.329 Script @Fill4Me/stdlib/event/event.lua:153: LuaEntity API call when LuaEntity was invalid.
stack traceback:
Fill4Me/fill4me/fill4me.lua:87: in function 'func'
Fill4Me/lib/event_extend.lua:84: in function <Fill4Me/lib/event_extend.lua:76>
[C]: in function 'pcall'
Fill4Me/stdlib/event/event.lua:148: in function <Fill4Me/stdlib/event/event.lua:127>

Which set of bobsmods are you using?

Added a workaround to try and avoid handling the bad entities that bobsmods appear to be passing around. See if 0.4.2 fixes your issue.

looks better - havent had an issue since :-/

thanks