I didn't check the model's firmware at the samsung web site because that's not a full model number. Sorry but I don't want to get it wrong.
I'd pick up the phone to 1800SAMSUNG and ask when a fix will arrive.
Consider the following scenario:
(1) You are watching TV and listening to the sound over your HT-F5500W.
(2) You mute the sound.
(3) The sound does not mute.
(4) You mute the sound a second time.
(5) The sound mutes properly.
If you again un-mute and re-mute it works just as you would expect. It seems to require a "long delay" for the above scenario to occur. If there is only a minute or so delay the mute works as you would expect (i. e. singe mute). The double mute only occurs after a "long delay"
(1) Do other people observe the same effect?
(2) Is there a way to disable this "feature"?