If you read through my old posts you will see that I actually applied for another study permit with new LOA from my new DLI. I got the new SP approved before travelling so I didn't have problems (I didn't envisage any).You entered Canada without any issues? I'm facing same problem. I submitted DLI transfer request outside Canada and my course is going to start on Jan 2022.
If you are changing course before attending your approved DLI, you need to re-apply for your study permit BEFORE you travel.