CFBookmarkMBS.CreateBookmarkData blocks for seconds

In testing 10.14.4 I find that this call:

CFBookmarkMBS.CreateBookmarkData(folderItem)

will block for over 3 seconds, if the OS decides I don’t have permission to access the file.

I’m mostly seeing this running debug apps in the IDE (2018r4).

Is this “normal”?

Could be, but you can use analyze process command in Activity Monitor to check what it is doing.
maybe a network query for some reason?
Is that a network drive?

I’ve not personally seen this; but I’d be questioning why you don’t have access.