Two of my colleagues went on hiatus.
I ate too much when I was on hiatus.
My question is, is “hiatus” actually a variable noun which can be used as an uncountable noun in the set phrases “be on hiatus” and “go on hiatus”? If so, doesn’t it mean the dictionaries are wrong? I see it being used as a countable noun as well in those phrases though. So I think instead of the sentences I gave above we can say these as well, right:
Two of my colleagues went on a hiatus.
I ate too much when I was on a hiatus.
Note: The context for the first sentence is, my colleagues took leave from work so they don’t go to work at the moment. In the second sentence, I say that I ate too much when on leave from work.