Hi I am a newbie, and have experienced this bug very recently. Earlier I thought that server might be busy or some temporary issue but turns out it is a well defined pattern.
whenever I open a problem and Then click on submit button to submit the code, after successful/ unsuccessful (invariant) submission you click on the submit button again in the nav bar, it redirects to a broken link and error page opens up.
Here I have tried to demonstrate the sequence.
PS: It might be true that only a particular region or part of community are facing this, so please don't downvote if you are not facing it because it actually exists!