Hi!
The best advice I can provide here is to, if possible, switch to using behaviours and Mox, following the advice outlined in Mocks and explicit contracts - Dashbit Blog, because this allows to keep async tests, and uses per-process expectations (even if it can be a bit harder to use in some contexts, in my experience), with clear boundaries.
On your specific question, also, without more code it will probably be a bit difficult to provide some help. If you have a way to share a smaller reproduction (and I know it can be hard to do), you will get more chance here! (or a bit more concrete elements).
