My Xiaomi Mi Flora sensor should send sensor values every 5 minutes to Homey. But I only get some of the values every 5 minutes. It can take hours and sometimes even days to get moisture value reading.
Also, do realize the moisture can be of the same level for hours. When other sensors do report more regularly, I think all’s fine.
Did you try to hold the sensor in a glass of water? How long did it take for the moisture value to be updated?