I should have reported this ages ago.
In the Channel Editor window, resetting the EQ tab (Alt-Click) merely bypasses it. Keeping the Alt key down, a second click will reset the EQ but leave it bypassed. One more click is required to get back to the action. Annoying, especially as the Channel Strip tab works as it’s supposed to.
I don’t understand why things that have worked perfectly in the past suddenly develop faults. This is not an isolated instance. What’s going on?