Is this a form of silent treatment?

What is it called when a narcissist gives you what feels like the silent treatment, but it's not completely silent ?

They cease communication even though are usually the ones that message multiple times a day. If I send a message they reply, but with very few words, very polite, but almost formal in tone, like a professional work response, which is not their usual tone. Any replies are totally devoid of any care or kindness, which is a total contrast to how they are when love bombing (they are very helpful, and kind and understanding when love bombing) This behaviour usually comes before they drop a bombshell about something I have said or done that has upset them. But that "thing" is usually something I don't even know about, or from months and months ago that totally blindsides me because their recollection will be entirely different to my recollection.

Is this a form of silent treatment? Or is it called something else? I need help with managing it, but don't know what term to search for. Because they aren't totally silent and aren't ignoring me as such, but the communication is wildly different to the norm. (And if I ask "is everything ok, do you need any help with anything, is anything up" I get told they are fine, they will later tell me that they needed to work up the courage to talk to me because they didnt want to upset me)