Some more information on this problem.
1. This appears to be an IE6 bug as I am able to reproduce the same issue against the dojo library.
2. This is reproducable against the JQuery web site using IE6.
The following Visual Basic Script can be used to reproduce the issue:
Set objExplorer = wscript.CreateObject("InternetExplorer.Application","IE_")
objExplorer.Visible = true
e = 0
do while e < 160 :
Obviously this is not typical behaviour for a user, but it would appear that it is something that should be guarded against if JQuery is to support IE6. I can in fact reproduce this without using a script if I simply change URLs quickly by hand.
Again, this is only reproducable with IE6. I am using IE6 SP3. 6.0.2900.5512.xpsp_sp3_gdr.090206-1234
Apologies for pounding the JQuery website yesterday @ 6:30.