After playing an announcement sonos muted

After I play an MP3 announcement using either Ivona or Google text to speech the sonos device goes into a muted state and does not return to the prior activity or state

As an example if I was playing a Pandora channel then played an MP3 announcement after the announcement the sonos volume becomes muted and the pandora channel does not resume playing.

Has anyone else experienced the issue, Best, Mark

Yes, I just put an "un-mute" action ahead of the announcement in an action group.

Thanks makes sense