Why does TextEdit still attempt to resolve href elements when opening HTML as code ?

On older OS's TextEdit would open an HTML file as text quickly.

I only recently discovered on High Sierra that although "Display HTML files as code" is chosen in preferences, any href elements that are in the HTML code are still being resolved before the content is displayed (as plain text)

This is a major pain for some files that contain many <link href elements because the system attempts to make a network connection for every element in sequence and this takes many seconds to complete.

Some files can take over a minute just to open as plain text.

If I disconnect from the network, the system still attempts to resolve all the hrefs

This is not what I expect from "Display HTML files as code"

I don't know whether the fault lies within TextEdit or the underlying file protection services, but I don't believe it should be doing this.

I can create a workaround with a shell script that changes the HTML content prefix to insert a character in front of <!DOCTYPE, and after that TextEdit opens the file in an instant, but that's a bit clunky.

Can anybody verify this for later systems ?