I'm seeing this too. Two days ago dosbox was upgraded from 0.74-4.2+b1 to 0.74-4.2+b2. I don't know what has changed in the new version, but everything used to work fine before the upgrade. This is in Debian testing, kernel 4.9.0-2-amd64, running on a Core i5-6400.
I'll also point out that using "core=simple" or "core=normal" is not a viable workaround for me, because they slow DosBox down horrendously.
