on openSUSE Leap 15.0 we have atm libreoffice 6.0.4.1 using system libraries we get following trace:

jack@quack2> oowriter ~/txt/foo.odt 
*** Error in `/usr/lib64/libreoffice/program/soffice.bin': free(): invalid pointer: 0x00007f6e7870fd78 ***

#0  0x00007ffff40ba0e0 in raise () from /lib64/libc.so.6
#1  0x00007ffff40bb6c1 in abort () from /lib64/libc.so.6
#2  0x00007ffff40fd427 in __libc_message () from /lib64/libc.so.6
#3  0x00007ffff4103c43 in malloc_printerr () from /lib64/libc.so.6
#4  0x00007ffff4105549 in _int_free () from /lib64/libc.so.6
#5  0x00007fffcd408754 in SEInitializerGpg::createSecurityContext(rtl::OUString const&) () from /usr/lib64/libreoffice/program/../program/libxsec_xmlsec.so
#6  0x00007fffcd8b5090 in DocumentSignatureManager::init() ()
   from /usr/lib64/libreoffice/program/../program/libxmlsecurity.so
#7  0x00007fffcd8871a0 in DocumentDigitalSignatures::ImplVerifySignatures(com::sun::star::uno::Reference<com::sun::star::embed::XStorage> const&, com::sun::star::uno::Reference<com::sun::star::io::XInputStream> const&, DocumentSignatureMode) () from /usr/lib64/libreoffice/program/../program/libxmlsecurity.so
#8  0x00007fffcd887dc0 in DocumentDigitalSignatures::verifyDocumentContentSignatures(com::sun::star::uno::Reference<com::sun::star::embed::XStorage> const&, com::sun::star::uno::Reference<com::sun::star::io::XInputStream> const&) ()
   from /usr/lib64/libreoffice/program/../program/libxmlsecurity.so
#9  0x00007ffff5b2efe6 in SfxObjectShell::ImplAnalyzeSignature(bool, com::sun::star::uno::Reference<com::sun::star::security::XDocumentDigitalSignatures> const&) () from /usr/lib64/libreoffice/program/libmergedlo.so
#10 0x00007ffff5b3ae2c in SfxObjectShell::ImplGetSignatureState(bool) ()
   from /usr/lib64/libreoffice/program/libmergedlo.so
#11 0x00007ffff5b3b399 in SfxObjectShell::CheckForBrokenDocSignatures_Impl() ()
   from /usr/lib64/libreoffice/program/libmergedlo.so
#12 0x00007ffff5b3b5f9 in SfxObjectShell::CheckSecurityOnLoading_Impl() ()
   from /usr/lib64/libreoffice/program/libmergedlo.so
#13 0x00007ffff5b60c40 in SfxObjectShell::FinishedLoading(SfxLoadedFlags) ()
   from /usr/lib64/libreoffice/program/libmergedlo.so
#14 0x00007fffd8d806b0 in SwDocShell::LoadingFinished() ()
   from /usr/lib64/libreoffice/program/../program/libswlo.so
#15 0x00007fffd8da994b in SwDocShell::Load(SfxMedium&) ()
   from /usr/lib64/libreoffice/program/../program/libswlo.so
#16 0x00007ffff5aef9dc in SfxObjectShell::LoadOwnFormat(SfxMedium&) ()
   from /usr/lib64/libreoffice/program/libmergedlo.so
#17 0x00007ffff5b61b57 in SfxObjectShell::DoLoad(SfxMedium*) ()
   from /usr/lib64/libreoffice/program/libmergedlo.so
#18 0x00007ffff6fcb1da in SfxBaseModel::load(com::sun::star::uno::Sequence<com::sun::star::beans::PropertyValue> const&) ()
   from /usr/lib64/libreoffice/program/libmergedlo.so
#19 0x00007ffff5b5e8ee in (anonymous namespace)::SfxFrameLoader_Impl::load(com::sun::star::uno::Sequence<com::sun::star::beans::PropertyValue> const&, com::sun::star::uno::Reference<com::sun::star::frame::XFrame> const&) ()
   from /usr/lib64/libreoffice/program/libmergedlo.so
#20 0x00007ffff57fd06a in framework::LoadEnv::startLoading() ()
   from /usr/lib64/libreoffice/program/libmergedlo.so
#21 0x00007ffff57ff942 in framework::LoadDispatcher::impl_dispatch(com::sun::star::util::URL const&, com::sun::star::uno::Sequence<com::sun::star::beans::PropertyValue> const&, com::sun::star::uno::Reference<com::sun::star::frame::XDispatchResultListener> const&) () from /usr/lib64/libreoffice/program/libmergedlo.so
#22 0x00007ffff57ffd78 in framework::LoadDispatcher::dispatchWithReturnValue(com::sun::star::util::URL const&, com::sun::star::uno::Sequence<com::sun::star::beans::PropertyValue> const&) ()
   from /usr/lib64/libreoffice/program/libmergedlo.so
#23 0x00007ffff54d6a45 in comphelper::SynchronousDispatch::dispatch(com::sun::star::uno::Reference<com::sun::star::uno::XInterface> const&, rtl::OUString const&, rtl::OUString const&, int, com::sun::star::uno::Sequence<com::sun::star::beans::PropertyValue> const&) () from /usr/lib64/libreoffice/program/libmergedlo.so
#24 0x00007ffff5c77554 in desktop::DispatchWatcher::executeDispatchRequests(std::vector<desktop::DispatchWatcher::DispatchRequest, std::allocator<desktop::DispatchWatcher::DispatchRequest> > const&, bool) ()
   from /usr/lib64/libreoffice/program/libmergedlo.so
#25 0x00007ffff5c7c1d3 in desktop::RequestHandler::ExecuteCmdLineRequests(desktop::ProcessDocumentsRequest&, bool) ()
   from /usr/lib64/libreoffice/program/libmergedlo.so
#26 0x00007ffff5c7fb22 in desktop::Desktop::OpenClients() ()
   from /usr/lib64/libreoffice/program/libmergedlo.so
#27 0x00007ffff5ac44c2 in desktop::Desktop::LinkStubOpenClients_Impl(void*, void*) () from /usr/lib64/libreoffice/program/libmergedlo.so
#28 0x00007ffff6a0a7df in ImplWindowFrameProc(vcl::Window*, SalEvent, void const*) () from /usr/lib64/libreoffice/program/libmergedlo.so
#29 0x00007ffff6858f78 in SalUserEventList::DispatchUserEvents(bool) ()
   from /usr/lib64/libreoffice/program/libmergedlo.so
#30 0x00007fffe204e276 in SalX11Display::Yield() ()
   from /usr/lib64/libreoffice/program/libvclplug_genlo.so
#31 0x00007fffe204d9d9 in DisplayYield(int, void*) ()
   from /usr/lib64/libreoffice/program/libvclplug_genlo.so
#32 0x00007fffe204dc9a in SalXLib::Yield(bool, bool) ()
   from /usr/lib64/libreoffice/program/libvclplug_genlo.so
#33 0x00007ffff685b03e in Application::Yield() ()
   from /usr/lib64/libreoffice/program/libmergedlo.so
#34 0x00007ffff6890125 in Application::Execute() ()
   from /usr/lib64/libreoffice/program/libmergedlo.so
#35 0x00007ffff5acce65 in desktop::Desktop::Main() ()
   from /usr/lib64/libreoffice/program/libmergedlo.so
#36 0x00007ffff68c3915 in SVMain() ()
   from /usr/lib64/libreoffice/program/libmergedlo.so
#37 0x00007ffff5c755b5 in soffice_main ()
   from /usr/lib64/libreoffice/program/libmergedlo.so
#38 0x000055555555479b in main ()

I asked Miklos and he said you Thorsten might know bit more about what is going on, as I have 0 clue about this integration.