[Bug?] Swarm of Crawling Claws can be unconscious, but not incapacitated

okay.... uhm.... these things are not immune to the unconscious condition but they are immune to being incapacitated...

https://www.dndbeyond.com/monsters/5174959-swarm-of-crawling-claws

...which created a problem when they failed a "sleep" from the bard and were below a "somnolence" from the warlock last session.

In that session i ruled that since they cannot be incapacitated, they are immune to being made unconscious by the sleep effects.

The two players argued that all the other monsters with immunity to incapacitation were also immune to being unconscious therefore these should be made unconscious.

I replied that it would make no sense for the creature to be both unconscious but also able to move around and take actions, but i would ask here for advice.

Is there an actual ruling on this, for future reference? I would say that if a condition has dependencies and you are immune to the dependency you are immune to the condition, but that's just my engineering talking for me. 😂

[EDIT: i just checked and the crawling claw (singular) https://www.dndbeyond.com/monsters/5194954-crawling-claw is actually immune to incapacitated too, but is also NOT immune to NEITHER unconscious NOR paralyzed, which, i never saw before. So... is this correct? Can they be put asleep OR paralyzed but also they keep crawling around and taking actions? it... does not make much sense.]

Quote from SimoneSpinozzi >>

okay.... uhm.... these things are not immune to the unconscious condition but they are immune to being incapacitated...

https://www.dndbeyond.com/monsters/5174959-swarm-of-crawling-claws

...which created a problem when they failed a "sleep" from the bard and were below a "somnolence" from the warlock last session.

In that session i ruled that since they cannot be incapacitated, they are immune to being made unconscious by the sleep effects.

The two players argued that all the other monsters with immunity to incapacitation were also immune to being unconscious therefore these should be made unconscious.

I replied that it would make no sense for the creature to be both unconscious but also able to move around and take actions, but i would ask here for advice.

Is there an actual ruling on this, for future reference? I would say that if a condition has dependencies and you are immune to the dependency you are immune to the condition, but that's just my engineering talking for me. 😂

[EDIT: i just checked and the crawling claw (singular) https://www.dndbeyond.com/monsters/5194954-crawling-claw is actually immune to incapacitated too, but is also NOT immune to NEITHER unconscious NOR paralyzed, which, i never saw before. So... is this correct? Can they be put asleep OR paralyzed but also they keep crawling around and taking actions? it... does not make much sense.]

 Maybe they felt like it was redundant to say that they were specifically immune to being paralyzed or unconscious if they were immune to being incapacitated because clearly if you're paralyzed or unconscious you're incapacitated so by saying they're immune to incapacitated they are clearly also immune to being paralyzed and unconscious. No need to say it twice.

I think you may be thinking too much into it. There are things which (talking 24 rules) give the incapacitated condition. The swarm is immune to them, along with a big pile of other things, as is common for swarms. 
However it is not immune to being unconscious. If they are rendered unconscious, then they do become incapacitated. They can’t be solely incapacitated, but they can be if it’s a sub-effect of a different condition.

The idea, as I understand it, was to avoid repeating the same text over and over in the rule book. So instead of under unconscious saying, you can’t take actions, etc. It just says incapacitated. 

The other fallback is, things only do what they say. It doesn’t say they’re immune to unconscious, do they are not. And if they are affected by it, they deal with all of the consequences. 

Quote from Xalthu >>

..
However it is not immune to being unconscious. If they are rendered unconscious, then they do become incapacitated. They can’t be solely incapacitated, but they can be if it’s a sub-effect of a different condition.
...

No, that's not correct

If a creature is immune to condition A, and condition B would also impose condition A, the creature ignores condition A

So while a swarm of crawling claws is unconscious, they would have the following:

Inert. You have the Incapacitated andProne conditions, and you drop whatever you’re holding. When this condition ends, you remain Prone.

Speed 0. Your Speed is 0 and can’t increase.

Attacks Affected.Attack rolls against you have Advantage.

Saving Throws Affected. You automatically fail Strength and Dexterity saving throws.

Automatic Critical Hits. Any attack roll that hits you is a Critical Hit if the attacker is within 5 feet of you.

Unaware. You’re unaware of your surroundings.

The fact Incapacitated can be imposed by other conditions does not bypass condition immunity

From the rules glossary on immunity:

If you have Immunity to a damage type or a condition, it doesn’t affect you in any way.

In general immunity to incapacitation or unconsciousness (vs immunity to specific effects that impose it) has a number of weird consequences such that it's probably not an immunity that you should actually put on a monster. In particular

• Being at 0 hp imposes unconsciousness. I guess if the DM isn't having monsters die at 0 hp, a air elemental (for example) can just continue running around and fighting at 0 hp, and maybe make a medicine check on itself?
• The petrified condition, among other effects, causes incapacitation. Thus, if you turn a crawling claw to stone, it can't move any more, but it can attack people who come in its reach.