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 for the report.
Looks similar to this:
https://mods.factorio.com/mod/autobuild/discussion/64eae78b7592fca060bc69ae

Hope, I have some time, soon

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