Mar 08, 2017 06:25 AM|Eric Du|LINK
According to your description, I make a test in myside in IE11, I only use AutoCompleteType="Disabled" in textbox, I found it run perfectly.
I look up the official document of this attribute in textbox, it supported form IE5+. So I can not reproduce your problem, but I found someone who meet the similar problem as you, I think you could refer:
“Autocomplete off” not working in IE - ASP.Net:
AutoCompleteType="Disabled" Not Working in Mozilla But Works in IE and Chrome: