I have Pale Moon installed on Windows 10. It has the uBlock Origin extension installed. This is how I reproduce the glitch:
I first clear ALL browser data and then close the program. Then I run this command to open that URL in Pale Moon (standard browser):
http://127.0.0.1/test.html
Now I again clear the browser data, close it and run the same command. This is repeated a few times. Soon, the page loads up without any styling applied. When this kept happening randomly like this throughout the day, I eventually checked the "console" and there it said this:
The stylesheet http://127.0.0.1/style.css was not loaded because its MIME type, “application/javascript”, is not “text/css”.
Why does that happen "once in a while", but not every time? Clearly my test.html file is not at fault here, since it works "most of the time" and it always includes this HTML header:
<link rel="stylesheet" href="style.css">
If, after it has failed, I press F5 to reload the page, it works every time, so it clearly is very "random" and closely related to the first page load after opening the browser, and not due to some error by me.
The webserver I'm using is PHP's built-in one. PHP 7.4.1. There are apparently never any errors logged in its log window. The only status codes I can see are [200] for "OK".
After a lot of experimentation, I have concluded that it's the crucial extension uBlock Origin's fault. When all extensions are disabled, this never seems to happen, but once I re-enable uBlock Origin, and that only, I soon get the same glitch again.
I have looked in the uBlock Origin interface but not found anything that might indicate why this was blocked and why it's not consistent. I have also searched but (as always) not found anything online about this.
It can't really be some kind of ad filter triggering this, because it doesn't happen every page load. It makes no sense at all to me. My only guess is that it's due to some kind of special protection mechanism used by uBlock Origin which (for unknown reasons) doesn't trigger every time.
What is going on? Please tell me I'm not going insane...
