The problem is actually located in libbootstraplo.so as the trace already suggested. Replacing the library with a "good" compilation confirmed it.
# Problematic frame: # C [libbootstraplo.so+0x1c4b8] stoc_impreg::mergeKeys(com::sun::star::uno::Reference<com::sun::star::registry::XRegistryKey> const&, com::sun::star::uno::Reference<com::sun::star::registry::XRegistryKey> const&, std::vector<stoc_impreg::(anonymous namespace)::Link, std::allocator<stoc_impreg::(anonymous namespace)::Link> >&)+0xb
https://cgit.freedesktop.org/libreoffice/core/tree/stoc/source/implementationregistration/mergekeys.cxx?h=libreoffice-7-1#n54
The problem is actually located in libbootstraplo.so as the trace already suggested.
Replacing the library with a "good" compilation confirmed it.
# Problematic frame: .so+0x1c4b8] stoc_impreg: :mergeKeys( com::sun: :star:: uno::Reference< com::sun: :star:: registry: :XRegistryKey> const&, com::sun: :star:: uno::Reference< com::sun: :star:: registry: :XRegistryKey> const&, std::vector< stoc_impreg: :(anonymous namespace)::Link, std::allocator< stoc_impreg: :(anonymous namespace)::Link> >&)+0xb
# C [libbootstraplo
https:/ /cgit.freedeskt op.org/ libreoffice/ core/tree/ stoc/source/ implementationr egistration/ mergekeys. cxx?h=libreoffi ce-7-1# n54