Activated, but my students in different groups can see each others’ comments.

I’ve got comments set up for lessons, and they are working–but even after activating the plugin, students from different groups still see comments. I’ve cleared all caches and everything. This is true for old comments as well as new ones, made after the plugin was activated. Is there a setting I’m missing to turn it on? Didn’t see anything else in the instructions. I’m using learndash 3.0–maybe the plugin is defunct now? Thanks for the help!