Medicare and Cobra
Cobra can be tricky.
When you move from active employer coverage to Cobra coverage, it feels and seems like the same coverage you had while working. However, in the eyes of Medicare, your Cobra coverage just became secondary to Medicare Part B (see the Who Pays First information below)
What that means is that you DO need to have Medicare in place so that they will be billed as the primary coverage.
You do have eight months to leave Cobra coverage without receiving a penalty for delayed Part B, however, we generally recommend leaving Cobra coverage immediately if you are over age 65 and Medicare eligible.
If you wait, you can run into issues with services being covered which isn't a good place to be.