The 384 upgrade worked fine for me. Having 
initially had the issue myself : (a return value of * after running: 
# nvram get dns_probe_content) and as 
@Matthew Patrick had previously posted below:
This was fully resolved for me by, right here: 
http://www.snbforums.com/threads/asuswrt-merlin-386-4-is-now-available.76498/post-733106 so my thanks for the quick recognition and post
I ran a dirty upgrade from 384_Beta3, corrected the above ^^ then another re-boot and it's all good.
IPv6 DDNS is a non-functional item, as posted here by 
@RMerlin > 
inadyn: rc: disable IPv6 support <
	
	
		
			
				
			
			
				
				Asuswrt-Merlin 386.4 is now available for all supported models.  This release merges with GPL 386_45958, and adds support for the RT-AX86S.  Dec 28th update: Updated to Beta 3.  Changes since Beta 2:  9288cd8c05 Updated documentation 8c0194de99 inadyn: rc: disable IPv6 support 0ae53e9cd8 rc...
				
					
						
							
						
					
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It 
seems... that this will be added back in, once ASUS have corrected / updated it themselves, in theory... in their next GPL RC-3 release(s) which, will then be worked on & improved 

 by 
@RMerlin