alt+r or "send tell" from chat2 menu isn't working in instances (eureka)

[AthenaTaso]

In eureka, when replying via alt+r or right-clicking and using the tell menu from within chat2.

Chat produces an error message that reads "Unable to send /tell. That party is no longer accepting members."

/r appears to work fine, right-click tell from social/adventurer list seems to work fine, right clicking a user and choosing "send-tell" also works as expected.