Is this only broken for me? I can fix the links by replacing <code>%2522</code> by <code>%22</code> but considering the link has been formatted like this since 2012 I'd be surprised if it is broken for everyone.
Topic on Template talk:Gerrit-reviewer
I also got this, and did some testing. Firefox (46.0.1) doesn't seem to understand that the %25 should be read as ". This worked in Chrome, however. Adding quotation marks inside the urlencode template instead seems to work. See User:Sebastian Berlin (WMSE)/Gerrit reviewer template.