Sample steps to reproduce:

1. Visit https://en.wikipedia.org/wiki/Special:NewPages (you should see "Hide bots | Show redirects")
2. Click "Show" in "Show redirects"
3. Click "Hide" in "Hide bots"

Expected: the applied filters are hideredirs=0&hidebots=1 and you can see the opposites of both filters (ie. "Show bots | Hide redirects").

Actual: only the last filter is applied, the previous one is forgotten (ie. some magic causes you again see "Show redirects").