This was something observed only just last night with a friend during testing of a factory, but they noted that for them the beam on the tools were not visibly shown on their screen while the tools were active in the welding process. I was able to see the working beam just fine as the world host at the time, but they could not see it on their end. Is the beam being visible dependent in any way on game settings for graphic details, or could this actually be a multiplayer bug?

I will see if we can test it further soon to confirm and hopefully update here if it gets resolved, but at the present time I am suspecting it to be a bug. No other tool mods or mods impacting tools were present in the world files other than this and toolcore at the time of testing.