I also got this segfault on startup immediately after upgrading to 5.1.3-2+b3 and I wanted to note that manually downgrading to the 5.1.3-2+b2 package on https://snapshot.debian.org/package/kmymoney/5.1.3-2/#kmymoney_5.1.3-2:2b:b2 is a good work-around until this bug is fixed.
Francois
