I had a look at your process model. It’s doesn’t contain any syntax errors so that’s fine.
The Conformance Checker is picking up on fact that in 10% of cases one of the three parallel activities is missing. However since it works by reporting the connections between activities that do take place when they shouldn’t as violations, rather than connections that don’t take place but ought to , it shows the violations you observed rather than ‘X activity is missing’ which is what I think you were hoping to see. Most of the time this approach is most beneficial for our users as it helps the user see which unnecessary activities they need to remove from their ‘as is process’. It’s worth noting that the Conformance checker reports the connection at which it is revealed that the case doesn’t have the process follow it ought to have, even when in some cases the actual cause for the case being deviant is at an earlier stage in the process. In your case ‘calculate capacity is followed by reject’ is a violation, not because the connection itself is deviant but because it signals that the window of opportunity for ‘check credit’ and ‘check system’ has closed without one or both activities taking place.
I hope this has helped you to gain a better understanding of how the Conformance Checker works.
I will raise your cases with our Product Development Team and see if in future releases the violation can be shown in the from you are expecting.