(posting here 'cos I just can't get the UK Ubi site to accept bug reports).
If you are standing on the pedestal in the balance position, and end yuour session ('cos you are tired after an evening battling the puzzles), then when you restart the game:
1) the pedestal is up
2) you are down, so
3) you are *inside* the pedestal... and can't get out
Unlike Uru, you don't carry a linking book, so you are stuck there, and all you can do is restore the previous explicit saved game (if any!)