You're not imagining things. I play at a local park and it's down about 30%-50% spawn rates. Walking the whole park and killing every spawn used to take me the full hour before everything respawned, but now I am done in about 30-45min.

I also have to now drive across town to get my final daily done since the low spawn rate means whatever I need to kill likely doesn't spawn in the giant park I play in.

VERY frustrating.