Reproduced in both Live 8 and Live 9:1. Add a Looper to a Liveset (new, existing, shouldn't matter)
2. Map a MIDI button to the record button in the Looper
3. Map another MIDI button to the stop button in the Looper
4. Make sure Live's transport is stopped
5. Press the record button. Now the Looper turns red, waiting for audio to come in
6. Don't actually play anything. While stopped, now press the button assigned to stop.
7. Watch the tempo do something weird
In Live 8, the tempo would go to some insane value; if I started at 100.0 BPM it would end up at 553.09 BPM. In 9, it would go to a more modest amount, such as 172.09 BPM. Can anyone else reproduce it?