Hi Dennis,
Shame we're now running two forums - I've just replied to your post in the 'other' one, and since I see that others here have largely echoed my views in their replies I'll post again here.
First of all, this sounds most odd, and I hope you weren't wearing any expensive trousers at the time
I've not heard of anyone else suffering from something like this with the 1.2.26 beta version, but judging by my own experiences with the Soundtower P12 editor I suspect it could possibly be some error at their end, resulting in the P12 bank memory being overwritten in some strange way.
I remember from many years ago that the Korg M1 could be persuaded to make all sorts of weird noises (unintended by its developers) by totally randomising the patch parameters and then sending that randomised data to the M1 itself, so it worked in unexpected ways. Some sounds were even released like this in commercial banks (IIRC it was Valhala's International Gold, although after so many years I might be wrong on this). Interestingly, these patches didn't warp the sound in odd ways if you loaded them into Korg virtual M1 - it was only the hardware that freaked out when faced with weird parameter values.
Perhaps your experience was something along the same lines. I would try working on editing your P12 module using its on-board controls for a bit - I suspect you won't have any similar problems, and if so would hopefully rule out an 'O/S memory leak' and point elsewhere
No doubt such things will be eradicated once we all finally get the official 1.3.0 O/S release
Martin