URL: https://www.bilibili.com/

Browser / Version: Firefox 139.0
Operating System: Android 10
Tested Another Browser: Yes Chrome

Problem type: Desktop site instead of mobile site
Description: Desktop site instead of mobile site
Steps to Reproduce:
Android 10 Firefox 139.0，我打开了 设置 > 网站设置 > 始终请求桌面版网页，然后打开 "https://www.bilibili.com/" ，随便点击一个视频，窗口会在新标签页打开，但网站显示的是手机版网页，并且在不管闭上述设置的情况下无法通过 下拉菜单中桌面版网站选项 切换回桌面版。假如不开启该设置，则可以通过 下拉菜单中桌面版网站选项切换桌面版。在桌面端浏览器中（例如 Windows 10，Chrome）没有此问题。In Android 10 Firefox 139.0, I opened "Settings > Site settings > always request desktop site" of the web page, and then open the "https://www.bilibili.com/", click on a video, the window will open in a new tab, but the site shows the mobile version. I can't switch to the desktop site through the "Desktop site" option in the drop-down menu. If this setting is not enabled, I can switch to the desktop version through the "Desktop site" option in the drop-down menu. This problem does not exist in desktop browsers (such as Windows 10, Chrome).

View the screenshot

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