Nc20, talk doesn't notify to android app on group conversations

We’re on NC20.0.8 & Talk 10.0.6 (the latest stable, I guess).

On direct talk conversations, notifies new messages to the android app as expected, but doesn’t to group conversations, doesn’t matter how is configured the conversation at the android app (mentions, all messages…). Never gets a notification. Only when the new conversation is created.

At the server, talk is configured for group messages for all messages.

What we could be missing for getting messages on groups?