Can monsters attack when they have a PC grappled? [duplicate]

This question already has an answer here:

  • Can one attack for damage after having grappled an opponent? 2 answers

Can a monster make an attack with a weapon that it is using to grapple with?
For example, if a Chuul has two player’s grappled with its two pincer attacks, can it still make a pincer attack? (Let’s ignore the tentacles for this example.)

Maybe this is a duplicate but I’ve only seen questions addressing player’s attacking while grappling and not vice versus. I also believe the answer is different because with player’s you need to have two free hands to grapple two creatures, but you can still make unarmed attacks (due to the openness of an unarmed attack) on your turn where as a monster has specific attacks.

To add some depth to the question, it seems to make no sense for a Chuul to grapple two players since it is now limited to its tentacle attack each turn as opposed to grappling only one player and being able to attack with one pincer and its tentacle attack. Was that RAI? A few other creatures fall in this category as well.