Shelly BLU motion blid time is not behaving as configured

Hi,

I have a Shlley BLU motion sensor. In the Shelly APP it is configured with a blind time of 30 sec (by default). But in HA, when I trigger motion and cover the sensor to wait for the “motion detection cleared” message, it arrives exactly 60 seconds after the motion stopped. This is not consistent with how the device is setup. Any ideas if this is a bug?