Gulp error node_contextify - Assertion 'args[1]'->IsString() failed

$ gulp
gulp[13360]: c:\ws\src\node_contextify.cc:635: Assertion `args[1]->IsString()' failed.
 1: 00007FF72C68DD8A v8::internal::GCIdleTimeHandler::GCIdleTimeHandler+4506
 2: 00007FF72C668886 node::MakeCallback+4534
 3: 00007FF72C66893F node::MakeCallback+4719
 4: 00007FF72C63CD70 node::DecodeWrite+13120
 5: 00007FF72CB95BF2 std::vector<v8::internal::compiler::MoveOperands * __ptr64,v8::internal::ZoneAllocator<v8::internal::compiler::MoveOperands * __ptr64> >::_Umove+79442
 6: 00007FF72CB96D59 std::vector<v8::internal::compiler::MoveOperands * __ptr64,v8::internal::ZoneAllocator<v8::internal::compiler::MoveOperands * __ptr64> >::_Umove+83897
 7: 00007FF72CB9609C std::vector<v8::internal::compiler::MoveOperands * __ptr64,v8::internal::ZoneAllocator<v8::internal::compiler::MoveOperands * __ptr64> >::_Umove+80636
 8: 00007FF72CB95FBB std::vector<v8::internal::compiler::MoveOperands * __ptr64,v8::internal::ZoneAllocator<v8::internal::compiler::MoveOperands * __ptr64> >::_Umove+80411
 9: 00000331E925C5C1