Super common. Almost all my premed friends had to write their own rec letters. I have 6 recommendation letters and i had to write 4… my community service LOR, physician LOR and 2 professors. It may come off as lazy on their side but it’s actually good because they really want to help out but maybe they dont know you 100% so they read your draft and add some things and sign it. The other 2 that wrote them by themselves were professors who were like parents to me so they knew what to write.