I’ve seen this issue, where either the sending device (e.g. the Blu-ray player) or the receiving device (i.e. the TV) remembers what went where, and doesn’t seem to respect swapped-about connections.
Strictly speaking, HDMI connections aren’t hot-swappable, though you can often get away with it; I would put both devices in at least Standby before swapping any cables.
But maybe you did, in which case I would tend to go one step further, and power both off at the mains, wait two minutes for any residual dynamic memory contents to decay, plug the HDMI cables back in, power on the TV and let it settle, soft reboot it by holding down the On key on the remote for five seconds, let it settle again, and only then power on the Blu-ray player.
See if that sorts things.
But you are doing well to reserve the ARC HDMI socket for a soundbar; ARC means Audio Return Channel, which will send your TV sound to a soundbar for enhanced audio performance.
ARC is wasted on the Blu-ray player, which can’t and won’t do anything with the returned audio, except camp on that particular HDMI socket, and stop you being able to take advantage of it with a soundbar or other audio-reproducing device.
Sure, you could use the digital audio out instead, but that is not as easy or as versatile as the HDMI ARC port.
YouView Superuser, but not an employee of YouView, nor retained by them for this purpose. It's purely me speaking
