The mod Autobuild (0.5.8) caused a non-recoverable error.
Please report this error to the mod author.

Error while running event autobuild::on_nth_tick(10)
'direction': real number expected got nil.
stack traceback:
[C]: in function 'newindex'
__autobuild/control.lua:407: in function 'try_upgrade_single_entity'
autobuild/control.lua:444: in function <autobuild/control.lua:430>
(...tail calls...)
autobuild/control.lua:937: in function 'do_autobuild'
autobuild/control.lua:1041: in function 'handle_player_update'
autobuild/control.lua:1047: in function <autobuild/control.lua:1045>

Thanks. I really need to do something about this error.

OK, I can't reproduce the error, but I added some additional nil checks.
If the problem keeps occurring, please notify me
Thanks!