Hello Valero
Spanning Tree doesn’t only apply to trunk ports, but is also active on access ports as well. So it is perfectly normal to see access ports in the blocking state. This is the case even if you’re using portfast, as shown in the lesson.
In this particular case, GigabitEthernet5/0/47 is actually a backup blocking port. This is a port state that we see when we use Rapid Spanning Tree. A backup blocking port will be used when there are two or more physical links between two switches. More about the backup port state can be seen at the following lesson:
I hope this has been helpful!
Laz