Thats how it is for me, I only noticed it because I was playing a song on my phone and noticed my timer went off full volume when earlier it was completely silent. I set a few alarms and tried no media volume which game me no alarm volume (when using a custom alarm sound not the default one) and full media volume which game me full alarm volume (again using a custom alarm sound). I do not know if this is the same case when using a stock alarm tone as all of them make me want to cut myself so I have not used them in years.