First, if you filed a Response to the original dissolution, your ex would not have been able to dismiss the case without your consent. Next, the case was (probably) assigned to the same bench officer to avoid the judge-shopping. If the matter is assigned to a COMMISSIONER, instead of a judge, the commissioner cannot hear any contested hearing without the written CONSENT of BOTH parties (a "Stipulation to commissioner"). Once they've done so, they then cannot withdraw their consent.
Finally, each party gets to disqualify ONE judicial officer, ONCE in a case, for no reason (a "170.6 challenge") IF the "challenge" if filed within a very specific time limit.
I agree with Mr. Gould-Saltman. Neither party has to agree to their case being heard by a commissioner. If/when the matter is assigned a judge, each side gets one opportunity to reject the judge, but then they run out of options. The judge shopping will end there. My sure you file a response to the petition; the petitioner cannot unilaterally dismiss the case after you do.
The answer to your question is not intended to provide you with legal advice you should rely on, only a general indication of what the law might provide. You may have provided only a limited description of your situation and I may be unaware of important facts that could affect your case. My answering your question does not create an attorney-client relationship between us.
Sign up to receive a 10-part series of useful information and legal advice about the divorce process.