Inserters -- and other things, but I'll stick to inserters -- can be connected to both the logistic and circuit networks at the same time. "Disable" has priority. If either network disables it, it is disabled.
This works, but the UI is confusing. It shows you the circuit network, unless you remember to click on the logistic icon. Nothing reminds you to click on it, to look there. It looks *exactly* like an inserter that's only on the circuit network, which it probably is, since 99.99% of the time your inserter is only on one network.
If this inserter is different, and it's really important to see those extra settings to know why it's mysteriously failing, nothing helps you see them.
I've had this problem in multiplayer, when someone set logistic conditions on train stations, that I was configuring in different ways. We had no idea why it was failing. I've also seen a reddit question "Why won't my inserter enable?" that confused everyone. The problem is rare, but when it happens it's extremely confusing.
Display When Unit Is Connected To Both Logistic & Circuit Networks
Moderator: ickputzdirwech
Re: Display When Unit Is Connected To Both Logistic & Circuit Networks
While I agree that such a situation is quite (but not extremely) rare, I can only vote in for such a feature; pretty much like the checkbox with 'Connected to Circuit Network <ID>" there should be a "Connected to Logistic Network" checkbox too. Those 2 small icons at the top can be confusing... (