SIRIL autostretch blowing out image

[sneaks]

Hello.
I have stacked and processed a few images with SIRIL and had no problem. Last night I stacked a new set of images, and the resulting FITS file is blowing out horribly when I apply autostretch.

The FITS looks ok when I open it, but when I change LINEAR to AUTOSTRETCH, this happens:
FITS file on left, mess on the right, obviously ;)

https://flic.kr/p/2kxBAPD

This is also happening when I open FITS files I stacked previously, without issue. I don't know why it is suddenly doing this.

Any ideas please?!?

[mswhin63]

Try colour correction first before stretch.

[sneaks]

Thanks, but I tried that, get the same thing. The nebulas go totally white and blow right out. Is it because I exposed more than I usually do? The lights for this sequence have the histogram about halfway, whereas they have usually been at about 1/3 from left. I wouldn't think that was a problem...?

I did manage to get a passable image by manually doing the stretching. It's just autostretch never failed me until now.