The mod Shield Generators (0.4.1) caused a non-recoverable error.
Please report this error to the mod author.

Error while running event shield-generators::on_tick (ID 0)
LuaRenderObject API call when LuaRenderObject was invalid.
stack traceback:
[C]: in function 'newindex'
__shield-generators/control.lua:590: in function 'set_right_bottom'
shield-generators/control.lua:895: in function <shield-generators/control.lua:594>

and when i thought they fixed this....

0.4.2 should address the issue

Thank you