Thank you for your suggestions. I usually use the remote, so I don't think that has anything to do with it. If I'm just stopping for a short time, I could use pause, but if I'm stopping for the day and not coming back to it until the next day, or, if I'm going to leave the underlying television program on while it's stopped, I normally wouldn't think of using pause.
I'm still puzzled by why it sometimes works the one way and at other times, the other way. If it's supposed to go back to 0, all right, but then why does it sometimes stay put?!!!