CMake Error set_source_files_properties (Ricardian contracts with clauses)

[chuck-h]

CMake Error at /usr/opt/eosio.cdt/1.8.1/lib/cmake/eosio.cdt/EosioCDTMacros.cmake:18 (set_source_files_properties): set_source_files_properties called with incorrect number of arguments.
with hello example when both hello.contracts.md and hello.clauses.md are present. Error does not occur when only hello.contracts.md is present.

No error if EosioCDTMacros.cmake is edited with quotes around the last argument to set_source_files_properties:
set_source_files_properties(${contract_sources} PROPERTIES OBJECT_DEPENDS "${contracts}")

ref https://eosio.stackexchange.com/a/6081/5783

eosio.cdt v1.8.1, CMake 3.10.2, Ubuntu 18.04