Penalty, bug or no bug

In our league race, there was a situation where I received a penalty under a short yellow. Reason for the yellow was a car spun on T1 at Spa about 5 secs in front of me. I went through T1 and the yellow came out. The spun car was at the pit exit wall. I did not see it but he was getting back going. I immediately get a message about illegal passing under yellow.
So a car spins, yellow comes out, that car gets passed and whomever is passing gets a penalty? If that is the case then you can't pass any car that is the reason for the yellow?