I got a message while playing that said this, "The mod Newly constructed machines wait for their modules (1.1.19) caused a non-recoverable error.
please report this error to the mod author.

Error while running event
newly-constructed-machines-wait-for-their-modules::on_nth_tick(60)
LuaEntity Api call when LuaEntity was invalid.
stack traceback:
[C]: in function 'index'
...onstructed-machines-wait-for-their-modules/control.lua:53: in function
'proxy_requests_item_we_want_to_wait_for'
...onstructed-machines-wait-for-their-modules__/control.lua:124: in function
<...onstructed-machines-wait-for-their-modules__/control.lua:122>

That was the error I got, all I did was paste a blueprint with modules in foundries over assemblers, then pressed the undid button a couple seconds later.