I first entered Canada with immigration documents in July. At that time, I directly set up a maple leaf card, and now my sister has set up a maple leaf card. Why didn't I get it?

The examination and approval of maple leaf cards are carried out separately. It's normal for you and your sister to collect separately. At present, the approval time of maple leaf card is generally about 8 weeks. I suggest you wait patiently for another two weeks. If you haven't received it, you need to call the immigration office to ask if there is any problem with your materials. The common problems are that the photos are not standard, such as showing teeth, covering eyes, and the proportion of head shape is not up to standard.

Specific standards can be found on CIC website.