In the case where you would get the message about the crowd being too loud for your players to hear you - This is caused by the fact that a live match is simulated in parts.
Many probably have noticed how there are pauses at certain times after a part of the match has been simulated. No comments no nothing. (If the pause is prolonged then your connection might be unstable or have some issues.)

The game basically shows this thematic message while it's processing data. I my self often get this message when playing the game via my 3G. It acts up on me sometimes and the server can't interact properly with my device.

So this certainly isn't a bug.

But if anyone tries to activate a bonus and NOTHING happens, not even the message pops up, then yep that would most likely be a bug. Might be caused by faulty internet connection though and not due to the code of the game - Button basically becomes non responsive. I would suggest quickly restarting the app.