>>51474315It's been that way since Diamond & Pearl, where Brock explicitly says that Ash's Infernape forgot Flame Wheel when it learned Flare Blitz.
It's referenced again in Sun/Moon, when Kiawe's sister says that Ash's Pikachu should use Catastropika too, but Rotom Dex points out that the Z-Move requires Volt Tackle, which Ash's Pikachu doesn't know anymore.
