Watch iOS mismatch, Can no longer pair phone and watch.

I was on iOS18. Taking a big trip and I had to revert back to iOS 17.6. After doing so, my Apple watch will not pair with my phone telling me that my phone needs to be on a newer version of iOS to pair.

I even re-installed iOS18 and re-paired, reset the watch and un-paired, reverted back to iOS17.6 and the same issue exists. Need to fix this ASAP!

[Edited by Moderator]