I see. Sometimes the value did not change enough for the threshold.
For some sensors the minimal value change is adjustable.
2nd, there’s no real detection system for sensors “keeping quiet”.
It’s also possible they’re on the edge of their range, or your, or close neighbour’s, 2.4GHz wifi is interfering sometimes.
Here’s a nice script with which you can check the last update status of (certain) sensors:
