I've been on this forum for about 10 years. That is why I can say the following with confidence.
There is NO pattern to when courses let people know. Some send letters in batches, some let interviewees know before those who don't have interviews. Some do it by email all in one go, or in batches. Sometimes there is more than one batch of interview offers. Sometimes reserve list people are told at the same time as interviewees, sometimes not. There is NO pattern. Do not speculate. Just don't do it. No point and it will add to your stress and anxiety.