The only constant in our industry in this day and age is that anything can happen to cause a perfectly functioning system to not work the way it used to.

At any give time the cable provider could have done an update disabling dual multi-channel output (or in rare cases changing they audio output format)

IF its an older integra 2-7 years, its probably the Integra as they have a very high defect rate with their HDMI board as the power supply is located directly below it and melts the solders when it heats up causing pre-mature failures.

Also note, that just because your Boss has been in this industry for 20 years A) doesn't mean they know everything B) may not be fully up to date on all the various weird problems we encounter; and the fact that he dismissed it means he should already know what's wrong...and if not he's some what arrogant.

This site is a great resource to eliminate Head meet Wall scenario's; and you've presented yourself well which goes a long way with us. Good luck and I look forward to hearing what your resolution is.