I noticed this as well. It's happened several times when I'm closing apps using the Recent Apps screen. It'll keep vibrating until I press the power button. Glad to see I'm not the only one experiencing it.
Sent from my HTC One X using Android Central Forums
Impossible cause i always have no more then 3 thing_open at a time. Music,messages, and browser. Even so i always kill anything im not using. :P
Still, this could be a sign of a busy processor.
When you start a vibration, you tell it how long to vibrate, but the OS renders this to a series of actions:
Start vibrate motor
Set timer to alert at stop time
---do other ---
Send Stop vibration
Now a real busy machine (lots of "do other ") might be late in getting around to this stop task, especially if all processors are busy. And the AT&T model only has two processors, so tieing up both of them on concurrent tasks might leave that thing running a tad longer. You wouldn't notice it the vibration was late on starting, or a web page was late on loading, but a vibration would sure get your attention.
Maybe this is why this particular bug is seen less often in the quad core devices, because they tend to have more cores free to handle these asynchronous tasks.
I got a call back from HTC escalation. Go to manage apps, all, find HTC.sense input and clear data. He wasn't aware of the problem, but said they just posted a new Rom with simple instructions on HTC.com-
I suggested he view the AC 1X forum. I'm not the only one who has this buzzzzzzzzz
Also- it doesn't stop until you tab a soft key.
I remember reading up on this somewhere... it said it creates an error file somewhere, and I was able to replicate it by pressing a button combo. If I find it again, I'll let you know here.
EDIT: Found it. bobmarsh72 of XDA writes: " We have found that holding down both the volume up and down at the sane time, will write a file in the bugreports folder in the sdcard. It takes about 20 seconds for this file to be created, once it is finished the phone vibrates quickly 3 times.
So next time you have the random vibrate, check the folder on sdcard called bugreports and see if a new file has been created, and check the time it was created. This will show that the random vibrate is the phone just writing the bugreport file."
Sure enough, I do have said folder, since this has happened to me as well.