When I import pins in the Pin Manager, I can see all of them. When I change their color, they just disappear. I can still see the name but not the actual pin.
Are you using SNAP 8 or still SNAP 7?
I just tried it in SNAP 8 and I couldn’t reproduce this problem.
I also don’t know that it exists in SNAP 7.
You can open the Layer Editor and change the styling. Maybe the pins come back.