Blank emails - "too much recursion"

I get occasional reports of emails that are showing as blank with a corresponding message of "too much recursion" in the Firefox Error Console.

Line reporting the error is ;

if(url){html[idx++]='<a target="_blank" href="'+url+'">'+AjxStringUtil.htmlEncode(tracking )+'</a>';}else{html[idx++]=AjxStringUtil.htmlEncode(tracking);}

or rather, the line that is highlighted when following the error link.

Seems to be HTML messages (to state the obvious) only.

All assistance appreciated.

You should post this as a new bug in bugzilla.zimbra.com and attach a sample message you see this happening with. Be sure to describe any specific repro steps if necessary.