The tech panel talk to each other during the reviews.
But in order to review an element, one of them has to call "Review" as soon as the element is completed. If it looks good to all of them from their angle in real time, they won't review it.
Possibly if they have become aware of chatter about a prominent skater's tendency toward a particular error -- from other officials, or commentators, or other coaches, or fans -- eventually they will start scrutinizing that skater's jump more closely and be more likely to call for a review, and to call the underrotation or wrong/unclear edge if they do indeed see it on the review.
If they do review and then don't make a call, that's because it looked good to at least two of them on the replay, which is likely from a different camera angle than what fans are seeing.
The judges don't decide who gets a ! or e call, or a << or < or q call. Those calls are the responsibility of the technical panel.
If they see a wrong edge or underrotation in real time, they can reduce the GOE right from the start and don't need to change it after the reviews. Even if there is no call from the tech panel, if a judge saw an error they can still reflect in their scores.
If the tech panel adds one of those calls during the review, judges are supposed to lower their GOEs by the appropriate amount if they hadn't already reflected the error in their initial GOEs during the program. Which could be from +3 or +4 down to +1 or +2 for the lesser errors.
Occasionally a judge might miss the fact that the call was added during the review. In that case that judge might send their scores with inappropriately high GOE for that kind of error. But if the call is made, most judges will reflect it and a judge who missed it will be an outlier.
If the tech panel does not make a call, the judges go with whatever quality they saw themselves in real time.
I think the judges do have access to the video themselves to replay elements they had questions about it. But they don't listen in on the tech panel reviews.