After upgrade to ember 3.15, helpers that yield promised recompute infinitely

I am having trouble zeroing in on this bug, but something happened when I upgraded from 3.13 to 3.15. In some (but not all) templates where I use the result of a helper in a let block, the helper will be rerendered infinitely.

If I don’t do anything with data, it’s fine. As soon as I try to use data for anything, it blows up. Specifically, I have examples of troubles with both promises and concurrency tasks. They’re very baked into my frameworks so it’s hard to break them out one at a time. I’ll have to work on that.

I’ve seen examples of how this has happened in the past due to bugs such as this one:

https://github.com/emberjs/ember.js/issues/14351

I also read about helpers that modify arguments to the helper thereby causing a rerender. But I’m pretty sure I checked that well and that’s not the problem.

The browser will slow to a crawl, and if I put console.log(‘hi’) statement in the helper’s compute function, I’ll see thousands of ‘hi’s. So I know it’s getting called over and over

I know this isn’t a very complete question, but I’m in a bind now and it’s the best I can scrape up.

Is there anything that can happen in the octanifying of my app that could make this happen?