Hi Eden,
Looks like some stages of your pipeline are hitting the 16MB BSON limit . My understanding is that you need to make sure that the output of every stage in your pipeline is less than 16MB (in your example, one of your stages is blocked from outputting ~21MB).
When I hit this problem for the first time I also felt like Mongo’s documentation could’ve done a better job at proposing possible solutions / examples of solutions (instead of just stating the limit).
Xavier Robitaille
Feather Finance