I’d assume your issue is that a promise isn’t properly being await-ed at some point. You can hover over types in the code repositories UI to help trace where promises are waited into real types.
I don’t think you need the async/await inside the map. You can just rely on the promise being passed through and then use the promise.all. This means you could just do await Promise.all(obj2s.map(o => this.fetchObjs(o, kvalue))), which should be a little easier to debug.
You can also try adding some logging right at the start of the fetchObjs method. You can also remove the await from fetchObjs and just return the promise from takeAsync.
You can also set breakpoints in the Code Repositories UI when running a Function in Live Preview, and use them to step through your code. That may be useful debugging any future issues like this!