[Bellman]

BBV - yes there is often a delay after trying to assign a tracker on BB, before it is shown and called.
But I think you will find faint tonals on that bearing in NB, and if you select one you can mark and assign a tracker.
Make sure if this contact is via TA that you justify it by eliminating the ghost first. OK you have no demon
until a BB replacement is available as you close range. You need to constantly monitor the BB bearing of this NB
contact and keep trying to assign, so that you can work demon and TMA.

You mention a delay also on marking in SA but my impression is that these,and the TA ones, are relatively short
in duration - around a minute and just a delayed response. If it is longer then it would be a cool SCS interpretation
of the senior sonar operator issuing instructions to a crewman to search with a following delay before success.
This type of 'memory' would nicely avoid the ''constant monitoring'' I doubt its a feature that is present in-game.