Current: upgrading pulseaudio breaks alsamixer

I have Slackware64 Current, pulseaudio / ALSA, and alsamixer, with this configuration. Until a few days ago I could use alsamixer to change change volume, the change was immediately effective for all applications using sound, and life was good. Then a few days ago I upgraded pulseaudio from 14.0 to 14.2, and alsamixer stopped working: pressing the up and down arrows no longer changes either the volume or the colored bar representing the master control. Other mixers (f.i. pavucontrol) seem to have a similar problem, basically the cursor is stuck at whatever level was set at boot. This happens as root as well as my regular user, and downgrading pulseaudio to 14.0 and rebooting restores everything to a working state.

Any idea what's going on?