How long do my games have to be to count towards experience?

I was playing SC2 today, and I decided to build a pool before any workers. I sent out 6 zerglings who then encountered my opponent's cannon cheese at the bottom of my ramp. I was able to destroy the cannon just after it warped in (lost one ling) ping then the probe who summoned it, then the second cannon before it warped in. After that, my opponent resigned. The replay says the match duration was 2:26, but apparently he resigned at 1:58. I didn't get any XP because the match was too short. How long does the game have to be to give XP?

After a short game, the experience tab is "greyed out", and when I hover over that tab, the following message appears: Experience tab disabled

Experience can be earned on Blizzard maps and
Extension Mods. Matches which end quickly or are
resumed from replays do not grant experience. This
section is also not viewable via match History

Possibly out of date, but this post on the battle.net forums claims they have to be at least 3:30.

Just tested this in a quick vs AI custom game.
HotS was enabled.
Was on Blizzard official Cloud Kingdom.
Put a very easy random race AI, chose random race for myself.
I won fairly quickly; no experience earned.
Before yesterday, this type of matchup awarded experience. Is this an intended change or a bug?


Just repeated experiment a few more times. It seems I was winning too quickly. Any wins under 3:30 in length awarded no experience. Those over 3:30 awarded experience as usual.