There is a bug that I reported for the newest Firmware (Version 184.108.40.206.384.81685 2020/03/06 59.05 MBytes) that I also reported for the most recent Beta prior to the new firmware released, but was not addressed.
1) Amazon Echo devices will no longer play any songs from Amazon Music (disables Amazon's Music service). Amazon will respond to a request to play music, but the song will not actually play.
2) Other device apps, such as the Coway Airmega system, will no longer be able to connect to devices on your local network. You can use a VPN (or a cellular connection) and they will connect fine. This means that it is definitely the new firmware. Also, if you downgrade to the version that was available prior to the most recent beta and newest public release, everything works perfectly.
I also tried manually opening all ports that could be used by Amazon Music and these other device apps which did not work either.
This is a bug that was reported as soon as the beta was released via the Asus ticket system and the support team said they would tell this developers. Unfortunately, it looks like it was not addressed for the post-beta release.
If anyone has an alternative solution, please post it. Also, if Asus reads these, please take the time to investigate this issue. I also wrote back to Efriam who was the support agent that indicated he would inform the developers of the problem.
With potentially thousands, if not millions of people who use Amazon Music via an Echo device impacted, I'm guessing this will be a big deal and the average person won't be able to figure it out (or will stop using Asus networking products).
Any help from the community is appreciated.