Not sure if that’s what you actually meant, but even Apple does not “upsample” ALAC; it sample-rate- converts LPCM from decoded ALAC. After which it directly D-to-A converts to the internal speakers, or recode back into ALAC if output over USB to a DAC.
Not surprising, it’s a pretty rudimentary sample rate converter. I wouldn’t call what Apple’s Core Audio does “upsampling” 