Canon says non-Canon lenses cause of semi-permanent body AF issues

I spoke again to Canon Tech Support as follow up to my email see thread page 5:

(see http://forums.dpreview.com/...t.asp?forum=1029&thread=34970402&page=5 Regarding AF Inconsistency on the Canon EOS 7D for f2.8 and faster using single center point HIgh Precision AF)

Canon told me that they had not heard of this high precision AF inconsistency.

BUT, they told me the usual Cause of AF system issues, is if you have used any non-Canon lens on your camera body, Canon has seen 3rd party lenses corrupt the EOS 7D and 5D MKII auto-focus systems even when you go back to Canon lenses.

He said that in 80% of the time a hard reset will fix it (removal of main and clock battery). Essentially, he explained that the 3rd party lens, uses reverse engineered capabilities that enable it to work with Canon's proprietary ETTLII AF system. Ultimately it can throw off the camera body AF parameters that it keeps stored.

I haven't tried it, but am curious whether for those of you who also experience(d) inconsistent AF on the 7D (with Canon lenses) - had you also mounted non-Canon lenses to your body? IF NOT, then the experiment holds for the high precision center low lighting AF point.
-Guy