I have chat fader off but for some reason it is fading out (classic era anniversary).

This feature is designed to hide the entire chat frame. When this option is enabled, hovering over the right side of the chat frame will reveal an arrow button.

If you are referring to the text fading out in the chat frame, it is unrelated to this feature.

To my knowledge, the automatic text fade in chat frames is a built-in feature of the Blizzard UI. The text will automatically start fading after 2 minutes of inactivity in the chat frame. You can verify this by temporarily disabling all addons.

If you want to disable this fading behavior, you can use the following Lua code snippet:

for i = 1, NUM_CHAT_WINDOWS do
    _G["ChatFrame"..i]:SetFading(false)
end

Yes i was refering to the text fading, sorry for that you can close the ticket.

By any chance is there any NDui feature to disable text fading? :D