Indeed.
The strange thing is if you right click and select 'Copy Link Location' on the top broken link and then paste into Notepad it comes up with
https://pprune.org in front of the flightradar address, though the pprune.org bit is weirdly invisible in your original post!!
Try it and see.
Also discovered if you highlight and 'Ctrl C' the broken link you should get the same result as above, (since highlighting and Ctrl C is the same as 'Copy Link Location' in this context) yet it produces a correct version of the link!!