28-135IS Bumps Image When Held Vertical

[Xtrema]

I've searched a few IS topics here, but did not see this. My new 28-135IS on my D60 works fine (focus, focus speed, sharpness). But, when the camera is held vertically, the first time it focuses there is a noticeable bump to the image. It is a single bump. Is this normal or should I send to Canon (after my vacation!)????

[tommykjensen]

This is the IS that stabilized the image. Absolutely normal and nothing to worry about.

[Ikinaa]

I noticed the bump too. It appears only sometimes.
Anyway, best is to wait for about 1 sec after IS has engaged before taking a picture so that IS can stabilize...