I'm sorry for that. It's the first time I use this page and I wasn't sure if a comment will be seen, because in MC-6941 Jon Atkins got no reply to his answer. Won't happen again.
The issue is not fixed at all. The (vanilla) Minecraft client does not query the DNS recursor for SRV records.
A look at the DNS queries (using Wireshark) shows that the current Minecraft client only queries for AAAA- and A-records but not for SRV-records.
Mojang, please fix it finally!
Technical details:
Minecraft version: 1.5.1
Oracle JRE version: 1.7.0_21 (x64)
Operating system: Ubuntu 10.04 x64
$ dig +short SRV _minecraft._tcp.whatevercraft.com
0 5 25565 server.whatevercraft.com.
$ dig +short A server.whatevercraft.com
46.228.200.240
Answering the questions, I would have to create a new server to replicate this bug. The affected devices were my phone and my laptop (host). There were no background processes running on my PC, but when I suspend the game on my phone, it sometimes disconnects from Microsoft services, which prevents me from accessing servers (sometimes, not always). It's like the game goes into offline mode. My server is properly configured; I didn't alter any properties, I only changed the world name and the default difficulty, While I have mobile data enabled on my phone, that's the only difference I have active. (Please note that I do not use mobile data at any of the times when the problem occurs, it's a insolated option enabled)