Gregatron said:

The deactivation sound appears to be there in the GOUT and the earlier mixes, but it's just buried much deeper in the mix.

Are you absolutely sure about this? because I definitely cannot hear it in either the original Dolby Stereo or the remastered '93 track.

Gregatron said:

Also, the SE mixes seem to have it come earlier in the shot, when the saber is still seen to be lit. So, this error seems to have been introduced for the SE, whereas the original got it right.

I'm a little confused by your description. Luke's saber is seen to be lit all throughout the shot when he runs out of the cave. That's why the deactivation sound of his saber is out of place there in the 70mm mix and SE, but you say that it's there in the other mixes as well, just buried much deeper in the mix, I may be wrong but I cannot hear it.

hairy_hen, I avoided to add those two sounds that appear in the '93 surround until we know for sure they're part of the 70mm audio.