"I was surprised that there were not more objections," from the defense team he added. "At one point, the court ... objected, because there was no objection coming from the defense."
Either they are bad lawyers or they were strategically withholding their objections in order to file the mistrial motion. I fully expect this to be brought up again in an appeal, assuming Trump loses the case.
As far as I'm aware nothing will stop them from trying to do that. It's up to the judge (or judges if it goes to an appeal) to decide whether their argument makes sense. While I'd hope that a competent judge will see their shenanigans for what it is, I have no doubt that someone has made that strategy work at some point.
To be clear, I'm not a lawyer, so naturally don't take my word for it.