I've encountered a crash bug, text copied here:
The mod Shield Generators (0.1.7) caused a non-recoverable error.
Please report this error to the mod author.
Error while running event shield-generators::on_research_finished (ID 18)
real number expected got nil.
stack traceback:
[C]: in function 'set_left_top'
shield-generators/control.lua:1135: in function 'on_built_shieldable_self'
shield-generators/control.lua:1310: in function <shield-generators/control.lua:1301>
Note that I just downloaded this today and was trying it out in an already well-established base. I was mostly interested in the AOE shields, not the individual turret shields, so I researched and built one of those first without issues. This crash then occurred immediately upon researching the turret shields tech, and only occurs when one of the AOE shield generators is already placed in the field and covering turrets.