Possible Neg SEO Attack. Any Danger in Temporary Links?

[Dymero]

For the past couple weeks, I've noticed a bunch of links coming from .cn domains that all seem to have the same or similar content. However, by the time I get to the sites the links are no longer there. I haven't been able to catch one with an active link.

So my question is, has anybody ever seen a link pop up on a site which was then taken down very quickly, and suffered any manual penalties because of it? If the link tracker I'm using is picking them up, surely Google is as well.

[aristotle]

Where do you see these links? Are they listed in Webmaster Tools?
If you only see them in your server stats or logs, most likely they are autogenerated referral spam or fake. Best just to ignore them. Soemtimes these are used to trick people into visiting sites that install malware on your system, so you shouldn't go looking for them, and as you said, you won't be able to find them anyway.

[Dymero]

Most of them are not in WMT but there are a few. I'm using Ahrefs to get more links. In any case, I don't want to rely only on what WMT tells me, since there have been cases where links not shown in WMT were cited in manual penalties.

I'm concerned that all these links popping up might be found by Google before they're removed and then used in a later manual penalty.

[ColourOfSpring]

Have you tried viewing the .cn pages in Google cache?