[mythtv] Rewind weirdness - known bug?

[zoiks2004-ivtv at yahoo.com]

I have some problems with rewinding live TV in myth. 
I've searched, but I can't find anything current that
matches this experience.  Here are the symptoms:

1) If I rewind for a few seconds, and then press Play,
the video continues to rapidly rewind and will either
stop minutes behind where I hit Play or more
frequently will go to the beginning of the ringbuffer.
 Sometimes it will also crash.
2) I see this whether or not I've set Myth to
"compensate for my reaction time" in seeking.
3) Rewinding/fast forwarding a recorded program does
not produce this effect.
4) Rewinding/fast forwarding a program while it's
being recorded also does not produce this effect.
5) I have a PVR350.  I see this while outputting to
the decoder, yuv interface (with teh latest ivtv
drivers), or to my vga adapter.  So I don't think it
has anything to do with the mpeg decoder, but it might
be related ot the encoder.
6) Skipping and jumping work fine and do not lead to
problems.

The last time I got it to crash I saw this in
mythfrontend.log:

[mpeg2video @ 0x408be854]ac-tex damaged at 3 26
[mpeg2video @ 0x408be854]Warning MVs not available
[mpeg2video @ 0x408be854]ac-tex damaged at 3 26
[mpeg2video @ 0x408be854]Warning MVs not available
[mpeg2video @ 0x408be854]ac-tex damaged at 3 26
[mpeg2video @ 0x408be854]Warning MVs not available
[mpeg2video @ 0x408be854]ac-tex damaged at 3 26
[mpeg2video @ 0x408be854]Warning MVs not available
2005-07-09 09:51:46.452 Using protocol version 15
2005-07-09 09:51:52.200 taking too long to be allowed
to read..
2005-07-09 09:51:57.201 taking too long to be allowed
to read..
2005-07-09 09:52:02.202 taking too long to be allowed
to read..
2005-07-09 09:52:02.202 Took more than 10 seconds to
be allowed to read, abortin
g.
Couldn't read file:
rbuf://192.168.99.201:6543/mnt/store//ringbuf1.nuv
[...then rebooted...]

Of course, I'm not sure what time the first few lines
occured at.  At about the same time, mythbackend.log
shows:

2005-07-09 09:52:02.204 Couldn't read data from the
capture card in 15 seconds.
Stopping.

This is in the 0.18-fixes version from svn, but the
behavior's been there for a while.  Is this a known
bug or should it be added to the bug list?  Or is
there some simple fix for it?