There are no guarantees. While eARC was supposed to free folks from having to use HDMI-CEC when using eARC, that doesn't mean a particular manufacturer doesn't require HDMI-CEC to be active in the TV and also on the receiving end when using eARC.
Many of the audio output glitches involving TVs featuring eARC and receivers that only support ARC come down to settings. Some TVs can re encode signals that exceed the bandwidth limits of ARC when connected to receivers that only support ARC. This can result in different issues using different combinations of components.
Whenever a device supporting HDMI 2.1 is introduced into a system, it is wise to replace ALL of the cables with Ultra Certified(48Gbps) HDMI cables so that the devices communicate there own capabilities and limitations to each other rather than have the cables do so based on their own limitations. Many still use High speed cables with newer systems because they seem to work but don't realize that cables supporting ethernet are required when eARC enters the arena and that video output will be limited by the bandwidth of High Speed cables vs Premium Certified and Ultra Certified cables.
It is not just helpful, but essential that folks having any issues with their systems post ALL of the details of their system. Information concerning the makes, models and the settings of each and every device are required for anybody trying to get to the root of the problem.
