Sadly, but that wonderful combinator didnotwork if they was placed by blueprint. Only character placed combinators work properly.

Maybe you did forget to place/blueprint a radar near it, if it's the couning one?
Mod handles on_robot_built_entity events exactly same as players' on_built_entity, so these should work exactly same, and they definitely do for me.

Double-checking event list, also noticed that factorio now has script_raised_built/script_raised_revive events which other mods might use to indicate that they created an entity, so added hooks for those in 0.0.10 as well, but that's unlikely to affect this issue, unless you actually have some mod that changes how robots work or adds some entirely different kind of construction robots maybe.

• I'd suggest double-checking if maybe you are missing anything first, as again, it should work fine with robots.

• If not a mistake, and you don't have too many mods or weird settings for these, maybe post a list of them, along with a more specific way to reproduce the issue (maybe only happens when you place combinators somewhere specific, or in a specific way?).

• And if previous one is not an easy option (like there's a 100 mods, some customized, and 1000 tweaked settings for them), I'd suggest unpacking this mod's zip in "mods" dir and uncommenting "conf.debug_log = true" in config.lua in it, then post what it prints (in factorio log or just stdout on linux) before and after building these non-functional combinators, in case it might be something other than detecting new combinators maybe (friendly biters in case of alarms? non-biter biters? biters on a different game surface? dunno really).

You could use Creative Mod for debugging. It has a setting somewhere (not at home right now, so can''t load Factorio to check myself) that will allow you to activate output when an event is triggered. Just start a new game, activate cheat mode, cheat yourself some entities, bots, roboports, and power, then turn on output for all events, place a blueprint, and see which events wil trigger. Perhaps there's something else you've missed ...

Yeah, did pretty much that - start new game, /cheat in console, place stuff, see that it all gets picked-up and works normally.
Guess you can indeed try doing that too as an option Sedrik, to check if bug might be easy/quick to reproduce without specific save and bunch of other settings/tweaks.

I made few tests and found the issue was because creative mode "instant blueprint" makes something wrong. If combinator was placed by player or construction robots then they work properly.
Thank you for your mod that saving hundreds megavat of power for laser defence.

"instant blueprint" makes something wrong.

Yeah, I think it might be this issue in particular:
https://mods.factorio.com/mod/instant-blueprint/discussion/5a5f1b0dadcc441024d75498

Fix there would be exactly to create these new script_raised_built events, which this mod started handling in last update (0.0.10).
( https://lua-api.factorio.com/latest/events.html#script_raised_built has more info on these)
Given how old that mod seem to be though (4y since last release), it almost certainly does not issue those, though I didn't check.

Problem is that mod starts tracking these combinators when they get built via these events, and if there are none, then it's just not aware of them existing on the map.
It has a hack to work around this however - config.lua has "conf.ticks_between_rescan = nil" option, which you can set to some reasonably-high value (e.g. "60 * 60" for wall-clock minute at 1x game speed) to just check whole map every once in a while and pick-up any yet-unknown detectors that way.
It's default-disabled because should be entirely unnecessary, but as I suspect you might be using a bunch of locally-modified mods anyway (like one mentioned above), one way to fix this "detectors created without events" issue is to just enable that rescan timer via minor local code tweak.
(more correct "fix" should be adding script_raised_built events to that other mod, as mentioned, but it might be more difficult to implement)

Thank you for your mod that saving hundreds megavat of power for laser defence.

Isn't whole point of factorio to generate gigawatts of polution irresponsibly though? :)