True. The first doctor who heard my murmur was in 2017. I was getting a physical completed as a requirement for an upcoming boxing match. He would not clear me of the physical until I got the murmur checked out by a cardiologist. I did visit the cardiologist, who clearly heard the murmur, but did not have time to get the echo and other tests he wanted completed prior to the boxing match. I really wanted to fight and so went to another doc who did not hear the murmur and cleared me for the fight. The night of the fight, the ring side doc also checked us out and cleared me- apparently he did not hear it- either that or he heard it and ignored it, not wanting to piss off 1,100 people who paid to see the fight, lol.
A year later I had another fight and saw a different doctor for my physical and no murmur was heard, once again. About 18 months after the murmur was first discovered, I did go back to the cardiologist and had him order the echo, at which time my aortic stenosis and BAV were diagnosed. Of course, I was very glad that I decided to go back and get things checked out.
So, yeah, in my experience, some docs hear murmurs and some don't.