Eeschema ERC failing in latest 5.99 build. Was successful in 5.1.5

Description

When upgrading my project to 5.99 latest build, the formally successful ERC now fails with "Invalid connection between bus and net items. Not sure if this is a bug in 6.0 or a new feature:

ERC_Failure_THS-80

Steps to reproduce

  1. Clone GitHub project THS-80 branch: master
  2. Run ERC on THS-80.sch

KiCad Version

Application: KiCad
Version: (5.99.0-1257-g7eeb34298), debug build
Libraries:
    wxWidgets 3.0.4
    libcurl/7.64.1 SecureTransport (LibreSSL/2.8.3) zlib/1.2.11 nghttp2/1.39.2
Platform: macOS Catalina Version 10.15.4 (Build 19E266), 64 bit, Little endian, wxMac
Build Info:
    Build date: Apr  8 2020 08:59:45
    wxWidgets: 3.0.4 (wchar_t,STL containers,compatible with 2.8)
    Boost: 1.72.0
    OpenCASCADE Community Edition: 6.9.1
    Curl: 7.54.0
    Compiler: Clang 9.0.0 with C++ ABI 1002

Build settings:
    KICAD_SCRIPTING=ON
    KICAD_SCRIPTING_MODULES=ON
    KICAD_SCRIPTING_PYTHON3=OFF
    KICAD_SCRIPTING_WXPYTHON=ON
    KICAD_SCRIPTING_WXPYTHON_PHOENIX=OFF
    KICAD_SCRIPTING_ACTION_MENU=ON
    BUILD_GITHUB_PLUGIN=ON
    KICAD_USE_OCE=ON
    KICAD_USE_OCC=OFF
    KICAD_SPICE=ON
    KICAD_STDLIB_DEBUG=OFF
    KICAD_STDLIB_LIGHT_DEBUG=OFF
    KICAD_SANITIZE=OFF