Related to bug 239960: Frescobaldi-2.19.0 depends on PyQt4 (my version is 4.12), which presently does not compile against sip-4.19. Frescobaldi, in turn, segfaults on startup. The errors with PyQt4 can be found at the bugreport above. There is also the bug report at https://github.com/wbsoft/frescobaldi/issues/838 detailing a similar issue with the "live" build of frescobaldi-3.0.0 (which depends on python-poppler-qt5) that appears to be resolved. Would it perhaps be possible to add a -9999 ebuild of frescobaldi to the portage tree to build off the git repository? That might serve as a workaround for the time being.
Correction: the correct bugreport is bug 604472. Sorry.
I've just pushed python-poppler-qt4-0.24.0 and frescobaldi-2.20.0. Please try again with these versions.
Also, please make sure you did upgrade to sip-4.19.1 already.