With the diaspora protocol, nothing is done with pulling per default. While the protocol has support for fetching public entities, this is not how communication works per default. diaspora works on a push-based delivery.
When you are a user on Node A, and post something, then Node A will push the contents to target nodes. The same goes for comments: if you write a comment on Node A, then Node A will push the comment to the target nodes (the parent’s author node, in the case of a comment). Nothing is pulled here.
If you comment a diaspora post on Hubzilla and they don’t show up on diaspora, then pushing to diaspora failed. This can either be an issue before the push happens (i.e. Hubzilla failing on building the payload), or an error causing diaspora to reject the payload. In case, I see a lot of rejected payloads from a wide range of Hubzilla nodes because the signature is invalid. Given that federation diaspora<->diaspora and diaspora<->friendica works just fine, it is a fair assumption that the error is on Hubzillas side.
You can observe diaspora’s
logs/production.log while Hubzilla is sending the comment to diaspora and maybe spot an error message, but the proper approach here would be to check what Hubzilla is sending in the first place, and to check if it’s a valid payload with a valid signature. The documentation for our protocol can be found here, and it’s usually a good starting point. If there are any specific ambiguities, we are usually more than happy to clarify those.
Unfortunately, my knowledge of debugging Hubzilla is exactly zero, and I don’t expect that to be different for anyone else here, which is why I suggested asking the Hubzilla devs.
The error about diaspora not being able to retrieve the software version is probably unrelated, and kinda expected. diaspora uses NodeInfo to detect the version of diaspora in use, and that’s nothing Hubzilla supports.