ASSERTION FAILURE at RecyclerObjectGraphDumper.cpp, line 45 with gc

hi, the following test case asserts at:
RecyclerObjectGraphDumper.cpp, line 45) dumpObject == nullptr,
(run the debug build with the -collectgarbage flag..):

function f() {
let a = [1,2,3,4];
Promise.all(a);
for (let e in a) {
CollectGarbage(e);
}
}

for (let t = 0; t < 100; t++){
f();
}

platforms:all
version: latest master compiled at: 13/4/2019