AS Path prepend behaviour in Palo Alto Firewall

What is the default behaviour of Palo Alto firewall when AS path prepend is configured?

• When there is no AS path prepend configured we will see the Local AS number only once in the rib-out table.

• If we configure AS path prepend value as 3 then in the rib-out table we will see AS numbers only 3 times and not 4 times. 

• If we configure AS path prepend value as 1 then will see AS numbers only once in the rib-out table.

• This is an expected behaviour on Palo Alto firewalls. 
• There is no RFC which explains how the AS path prepend must be implemented. Hence the implementation of the same is open interpretation