The problematic gameplay involves all creatures that can mark and all creatures they mark to a greater or lesser extent.
The problem only exists for creatures that can lay down a mark for a duration other than a turn. That's Divine Challenge (easily circumvented) and this -one- monster. Oh and a single Fighter power, maybe.
I just don't see the need to go all errata on this. One is circumvented by a shift of one square... is an errata -really- necessary just to cover -one- single monster?
The perverse incentive to continue pounding a dropped or even dead foe (include the dead enemy in a fireball to avoid the -2...) just because he marked you while alive is bad from a gamist perspective pretty much no matter what, particularly when the PC's are doing the marking (as is usually the case).
That's not much of a problem. Very few PC marks have any sort of persistant duration. I have no problem with a mark lasting while the PC is dying. If you're that low on hps to begin with, maybe marking is a -bad tactical decision- and this is one of the reasons why.
If there's a need for errata, it's for what effects do and don't go away when you die. That's a problem with -death- not with the marking rules.
Then there's the in-game believability issue, being that the interpretation of many marks (which are already tricky in the first place) becomes a laughing stock when the marking creature is dead. I don't need rules that undermine the tone of the adventure and turn the game into something best made fun of.
Again, the problem is the rules for character -death- and how it applies to effects in general, not to marks themselves. Let's focus on the -real- issue here.
The DM can fix everything. That's a cop-out: I suggest every DM fix this matter, and what better way to suggest that to every DM than by embedding it as part of the rules.
-If- there is errata necessary, it is -not- for the marked condition. As indicated above, the problem is in how death effects effects in general. -That- is where the rules break down.
Other than that tho, marking works -just fine- and thusly, errata are a waste of resources.
EDIT: Not having my books handy, isn't there something that says your effects end if you die? If that's the case, well, then marking is certainly covered as well. I know I use that as a houserule, with the exception of save ending conditions.