I also get a similar message using a Stages power meter. I am able to connect using the UI method :
public void requestAccess(Activity userActivity,
                 Context bindToContext,
                 boolean skipPreferredSearch,
                 int searchProximityThreshold,
                 AntPluginPcc.IPluginAccessResultReceiver<AntPlusBikePowerPcc> resultReceiver,
                 AntPluginPcc.IDeviceStateChangeReceiver stateReceiver)
but I'd prefer to use the non-UI method to connect when the device is already paired. Looks like all messages can be received with the method above.
Also, has my post about a faulty response from the non-UI requestAccess method for Bike Speed & Cadence been verified?
Tom