Cities disappearing when scouted

[KillerFugu]

W176. I used to see a bunch of inactive cities on my map. I started scouting them for resources and they simply disappear. I've even farmed one and gotten resources and then had that city disappear. I this normal behavior. I'd like to be able to farm these before they barb out. I'd also like it if the turned to barbs rather than disappear.

[LordFirefall]

That's normal. Those players have gone inactive and they get deleted when attacked.