They were submitted at the same time.

koji list-tag-history --tag=f20-updates-testing --package=hornetq
...
Thu Jan 23 11:53:37 2014: hornetq-2.4.0-4.fc20 tagged into f20-updates-testing by bodhi
Thu Jan 23 11:53:47 2014: hornetq-2.4.0-3.fc20 tagged into f20-updates-testing by bodhi

As you can see the tagging operation for -3 occurred after -4

Here is what happened next:

koji list-tag-history --tag=f20-updates --package=hornetq
Wed Feb 5 10:30:31 2014: hornetq-2.4.0-4.fc20 tagged into f20-updates by bodhi
Wed Feb 5 10:33:02 2014: hornetq-2.4.0-3.fc20 tagged into f20-updates by bodhi [still active]
Thu Feb 6 09:48:24 2014: hornetq-2.4.0-4.fc20 untagged from f20-updates by limb
Thu Feb 6 09:48:24 2014: hornetq-2.4.0-4.fc20 tagged into f20-updates by limb [still active]

You untagged the -4 version from updates today.
This should eventually work it self out.

However, looks like -6 is in the queue:

Wed Feb 5 10:30:32 2014: hornetq-2.4.0-6.fc20 tagged into f20-updates-testing by bodhi [still active]

good luck!

Right. I've run into this countless times, I've only just recently been able to fix it myself, by forcibly re-tagging -4, in this case. I don't think -6 will affect anything, since it's headed for updates-testing.

Present.