Position 6 google penalty. fact or fiction?

[Michael Martinez]

MIchael could you elaborate on that further, i was always under the impression that getting and losing backlinks in a short period of time would seem unnatural, so far my stance was always make your backlinks look as natural as possible.

There is nothing unnatural about losing a link. It happens more often than most people are aware.

Whether a link can cause an over-optimization penalty is a matter for speculation (not argument). The only way I know to be sure (short of getting someone from Google to confirm the hypothesis) is to remove the link, see what happens, put it back, see what happens, etc.