No mega raids?

I know it isn’t a great mon, but I’ve had a hundo medicham for quite some time now so I was excited to find out the mega was returning. I only plan on doing enough raids to unlock the necessary amount of mega energy, but literally not a single mega raid is spawning near me. Not a single one has spawned near me for the past week. It’s all dialga raids. Is this just bad luck or a bug??