When resolving server location through DNS SRV records, MC ignoring priority and weight, blindly trying the first record returned by query.
Furthermore, it is retrying the search when an attempt is made to connect to a given server that currently marked as available.
Reproduction steps:
Set up your DNS resolution like this:

$ORIGIN example.com.
primary A 127.0.0.1
secondary A <some.fake.ip.address>
_minecraft._tcp.mc SRV 1 5 25565 primary
_minecraft._tcp.mc SRV 5 5 25565 secondary

Start server and client on the same machine.
In client, add "mc.example.com" to the list of servers.
Repeatedly tap "Refresh" button.
Observe the server coming in and out of availability.
When the server listed as "Available", attempt connection.
Observe the connection error with no further explanation.

Ref: http://tools.ietf.org/html/rfc2782#page-3