Hi,
Like stated in the subject, during cut time while the “Use common time note grouping” time signature property is activated, the metronome is also behaving like the time signature would be set to common time, meaning four clicks per bar instead of two. Of course this might be the intended behavior, but personally, it makes way more sense that the metronome is consistent with the (visibly given) time signature rather than the choice of note grouping.
All the best!