Note from Michael Lowe @ BP:
This I not really a problem with wait stages as Blue Prism naturally iterates through the DOM repeatedly looking for the element (for the allotted period of time). However with reads, writes and navigates it will only attempt it once (throwing the classic element not found error if the element doesn’t exist). Possibly having these stages try a couple of times automatically would resolve this issue, but that’s not the way the product works right now. I will raise it as a product suggestion which will get considered for a future development.
This was in response to our continued problems with Invocation errors on Edge/V6.9