tests/doc/exJ8.block: triggers assertion

When compiling the latest code in master (v8.6.2-39-g2afaa6dc), I am getting the following error while converting exJ8.block into a pdf:

make[1]: Entering directory '/home/dirk/src/msc-generator/doc'
  MSC-GEN  exJ8.pdf
msc-gen: contour.cpp:425: void contour::Ray::CalcAngle(): Assertion `0<=angle.angle && angle.angle<4' failed.
make[1]: *** [Makefile:1144: exJ8.pdf] Aborted (core dumped)

I am compiling under Linux using:

./autogen
./configure
make