There's a problem in browser version recognition code. Mail.Ru Agent software adds its version in IE userAgent string like this:

mozilla/4.0 (compatible; msie 7.0; windows nt 5.1; mra 4.9 (build 01863))

Notice the mra word added by mail.ru agent. It confuses jQuery browser version detection code:

jQuery.browser = {
    version: (userAgent.match( /.+(?:rv|it|ra|ie)[\\/: ]([\\d.]+)/ ) || [0,'0'])[1],
    ...
};

In this case the version detection regular expression erroneously considers that browser version is 4.9.

To avoid this bug I suggest using full engine names insted of two-lettershortenings in browser detection regexp. Example:

jQuery.browser = {
    version: (userAgent.match( /.+(?:rv|webkit|khtml|opera|msie)[\\/: ]([\\d.]+)/ ) || [0,'0'])[1],
    ...
};