I reflected quite a lot on the frustrations of both teachers and students in online collaborative learning. I started by reading quite an interesting paper [1] that outlined some of these issues:

Even if some of these issues seem generic enough to be applied to any collaborative learning tasks, I think many of the challenges are exacerbated by the online setting. In my experience as a teacher in different online courses in which students collaborate with each other, I think that poor feedback on collaborative assignments can influence the progression of the students. My approach to deal with this is to make sure that we as teachers ask for feedback early and give feedback early and often during such collaborative assignments.

Another aspect relates to cognitive distances that can have an impact on online collaborative learning. These distances are not well studied, as far as I can see, in the online teaching literature. I experienced concerns from students that distance is making communication more difficult. Finally, I observed that it is more difficult to motivate students to continuously perform collaborative assignments if the instructions are not clear.

Overall, I recommend evaluating these challenges and good approaches to online collaborative learning.
Nevertheless, when developing online courses one should try to address the challenges I mentioned and how these assignments are supported by all the needed instructions and details. I am sure that there are mitigations to the described challenges that are already known to other domains. For research, I am curious if there are other experiences provided that are useful. Understanding collaborative learning in an online setting is not a trivial approach, and further research would be needed to gain more insights. I invite other researchers to revisit in other contexts the experienced challenges and good approaches. Please comment below if you have any questions or remarks we can discuss.

References

[1] Capdeferro, N. & Romero, M. (2012). Are online learners frustrated with collaborative learning experiences?. The International review of research in open and distance learning, 13(2), 26-44.