Success! I have had delayed, and absent notifications after my Android went into DOZE mode after about 45 minutes. My APPs are set to exclude WYZE from the DOZE mode. Tried everything, without success, with help of WYZE technical assistance. Apparently the WYZE APP cannot break through the DOZE mode. I have been able to work around the issue by turning off WYZE notifications and using IFTTT and creating a WYZE/PUSHOVER service for notifications. So far, so good.