"The TV sound and the sound bar were not in sync"
Some systems are persnickety and need to be powered up sequentially. Such as power on the TV, wait a few/15 seconds and then the soundbar, extra stuff.
Tv I guess needs to recognize the arc/hdmi stuff first.
As a side note. HDMI wasn't created to give us consumers (I actually hate that label)more media goodness, but to stop us from making copies for ourselves because big providers consider anyone with a computer a criminal who is stealing their sales profit. So with digital, which was pushed forward mostly because it could be encrypted needed a way to stop the chain of copying. HDMI cables actually has circuitry in them to facilitate encryption to stop pirating. Any device using hdmi has to be okayed for use by the hdmi standard. Hdmi is a physical wall to stop us from making copies. It's not well known, but when hdmi first came out, it practically bricked any and all devices just starting out with the standard as well.
It took the hdmi association or whatever they call themselves a pretty good rewrite of the specs to allow our legacy devices to work. Everyone manufactures all the stuff in now.
The bigger bandwidth and all that happy stuff they like to spout is almost a side dish extra left over after piracy safe guards.