iPhone bug: Unresponsive visual Voicemail scrubber bar

When playing back a visual voicemail for the second time, dragging the time slider playhead jumped the voicemail to the proper time, but it then stuck at that time. The voicemail played properly, but the playhead no longer moved, unlike the initial playback of the voicemail. I tried a second time by going home and trying again. This time it worked fine.