I'm getting some strange behavior if I set a value of out to zero.

This is my code:
out = {}
out.coal = 0
out.wood = 1
delay = 60

On the right it says:
[out-invalid] wood = 1

There is an output of wood 1 coming out of the combinator.

If I remove the out.coal = 0 line, then I get
[out] wood = 1 on the right side.

Is the invalid a problem? Should I be doing something differently to not get that?
In my actual code, I don't often set it to the constant 0, it's the result of some calculation.

Was only a problem in that GUI signal-printer panel, where =0 signals instead of being skipped, stopped the output at that signal, printing all leftover ones as erroneous. Shouldn't have affected the actual combinator output, just a bug in that listing on the right.
(apparently introduced in 0.0.66 because I mislabelled "cb_slots_end" as "cb_slots_skip", while it was more of a "no more signals" label)

Should be fixed in 0.0.75. Thanks for reporting!

Thanks for all of your work.