I reviewing a paper and now getting the revised paper for the next round. Although it has improved overall, in some parts, the paper has become worse when the authors followed (in my opinion) poor advice from another reviewer (I can see the other peer review). Is it appropriate to advice the authors to ignore the advice from the other reviewer and revert this particular change? It concerns a minor point.
Ask yourself whether it is worth it for a "minor point". But you can ask the editor for advice. And, as you suggest, you can also just give your best advice for the fix. You don't need to speak badly of the other reviewer to do so. Just say what you think the authors should do to make the paper better.
Conflicting reviews are common enough.