Many an ISP block those ports.. But they you would think they would just drop, not sure why they would send reject.. But guess it is the nice thing to do ;) Just you almost never see that on firewall.. Because if your sending me packet I don't want, why should I spend bandwidth and cycles telling you.. Unless you were on my network… From the public internet sure not going to spend effort letting answering the noise.. I reject inbound, so if client tries to go outbound on a port I prevent they get a reject.
Do you scream go away when the jehovah witness comes a knocking at your door or do you just ignore them until they go away ;) You sure don't want to get up and answer the door just to tell them go away do you.. Better to just sit back on the couch and finish your beer..
Only thing I reject from internet is traceroute udp ports, so my my traceroute to on ipv4 or through via ipv6 see the hop ;)
But yes as stated - great test is to sniff for it on pfsense wan.. If pfsense doesn't see it even - sure couldn't be sending reject..