Current enblend fails due to lack of memory for tasks which worked using 3.2

Trying to stitch 21 photos in a hugin workflow on Arch Linux, enblend fails after 10 photos (release version) or 12 (hg version, unless it just got further this time because I'd closed some other program), like this:
enblend: info: loading next image: P1070312-P1070332b0000.tif 1/1
enblend: info: loading next image: P1070312-P1070332b0001.tif 1/1
enblend: info: loading next image: P1070312-P1070332b0002.tif 1/1
enblend: info: loading next image: P1070312-P1070332b0003.tif 1/1
enblend: info: loading next image: P1070312-P1070332b0004.tif 1/1
enblend: info: loading next image: P1070312-P1070332b0005.tif 1/1
enblend: info: loading next image: P1070312-P1070332b0006.tif 1/1
enblend: info: loading next image: P1070312-P1070332b0007.tif 1/1
enblend: info: loading next image: P1070312-P1070332b0008.tif 1/1
enblend: info: loading next image: P1070312-P1070332b0009.tif 1/1
enblend: info: loading next image: P1070312-P1070332b0010.tif 1/1
enblend: info: loading next image: P1070312-P1070332b0011.tif 1/1
enblend: info: loading next image: P1070312-P1070332b0012.tif 1/1
Killed

I see this in the system log:
Dec 05 01:36:02 archie kernel: Out of memory: Kill process 4067 (enblend) score 562 or sacrifice child
Dec 05 01:36:02 archie kernel: Killed process 4067 (enblend) total-vm:969536kB, anon-rss:838156kB, file-rss:8kB

I have 1GB of ram and 512MB of swap (and a pretty lightweight software environment), which isn't much these days, but the panorama I'm trying to stitch isn't huge either - the biggest file is 2506x2640, or 16MB. If I try enblend 3.2 it successfully stitches all 21 files, and doesn't even take very long.

Has enblend changed the way it does things so that vastly more ram is required than previously? Is there some option I need to use now if I'm a little short on ram? Or is this a bug? If it simply requires a lot more ram now, perhaps it is worth advising people to use 3.2 if they run into trouble.