Regression in compression efficacy

[ottok]

I noticed that versin 1.2.3 produces a smaller file than version 1.3.0:

# On Ubuntu 14.04
$ jpegoptim talouspaperia-rintsikansuojana-lowres.jpg 
talouspaperia-rintsikansuojana-lowres.jpg 3000x1688 24bit P Exif JFIF  [OK] 292347 --> 292347 bytes (0.00%), skipped.
$ jpegoptim --version
jpegoptim v1.3.0  x86_64-pc-linux-gnu

# On Ubuntu 12.04
$ jpegoptim talouspaperia-rintsikansuojana-lowres.jpg
talouspaperia-rintsikansuojana-lowres.jpg 3000x1688 24bit Exif JFIF  [OK] 292347 --> 286527 bytes (1.99%), optimized.
$ jpegoptim --version
jpegoptim v1.2.3  x86_64-pc-linux-gnu

File http://www.puutalobaby.fi/wp-content/uploads/2015/09/talouspaperia-rintsikansuojana-lowres.jpg

Is this a regression in something?