Hi Nick,
I don‘t think there is a problem with your Emerald. Mine does it the same way.
It’s the typical (good) Novag time management on tournament level. The more moves you make in a very short time the more time the computer saves for computing the next move.
For example, when it is in its opening book for, let’s say, 20 moves, then has to calculate, it takes often longer than 20 minutes for the first response (on tr7).
The same happens when you use the referee/multi move function to reach a specific position. Emerald counts the number of moves from the new game position and thinks: oh, it’s move 18, I haven’t spent any time so I’ll look at the next move for 20 minutes.
Best regards
Roberto