Bad RNG or is it really true?

Do you have the exclusive move on your starters? Blast burn, frenzy plant? If so, I heard that those prevent you from getting that third charge move people are looking for.

Just bad RNG. I set Sludge Bomb on my Venusaur, Ice Beam on Blastoise, Solar Beam on Typhlosion on my first CTM. Only DC on Charizard took me about 4-5.

Bad RNG. My Metagross got earthquake in 2 tms and blastoise got ice beam instantly.

Seriously, though, buy the second move, if it isn't what you want, TM it once. If that doesn't hit it for you, wait until tomorrow and TM it again. Sometimes they get stuck in a rut on a given day, switching back and forth between the ones you don't want.

If everything fails you might have to do a sacrifice: Send your best legendary to the professor, then try TM'ing for your favourite move again. It is said that this works in about 40% of all cases.

I did BB Charizard 2nd move...started Fire Blast--Overheat--Fire Blast--Overheat...then instead of doing more TMs I decided to get a 2nd move on a 100% fire Blaziken 2441cp, it learned Focus Blast on its first try...however, turns out Blaziken with 2 one bar moves is not ideal in battle.