Issues with embedding from RSS

As I wrote here a couple of weeks back, using a different feed solved the permalink problem. But now the plugin is not fetching the contents of each item.

The topic is created with the correct title, from the right user and filed under the appropriate category as configured. However, the body of the topic says something (sorry for the imprecision, I am using the portuguese locale) like “this is a discussion related to this original message” and points to the right URL.

Then there is a button labeled “show full message”. When I click it, it stays “loading” for indefinite time. I had the understanding that if I came back to the topic a second time, the cache would have been created but that does not seem to be the case.

Example:
https://rede.tropixel.org/t/greentech-alliance/418

The feed source is this:

Any tips are welcome.