I had a similar bug with outgoing attacks. The time runs out, but still nothing happens, no CR or something else. If the flight is aborted, you can see that the ships have flew even further than the target was. For example a probe should fly about 3 minutes, if you abort after 7 minutes (=4 minutes after the not happening impact), the probe needs 7 minutes to find its way home.

You reported it, any missuse of it is categorized as bug using, any if someone things he can get away with it its wrong, GO Tool fleet log tracks everything

What is in overview of units screen? Does that show correct fleet movements?

Fixed this. I'm not sure yet why the fallback didn't worked ... :-/
Espionage Probes have an attack value of 0, to prevent division by zero issues the value is set to 0.001 ... This fallback magically didn't worked anymore :-/