Fast ping false down


I have an issue with fast ping at librenms i change the ping frequency to 30 seconde and leave the polling frequency 5 min then i added 180 deviced as ping only.
The issue is all devices still send false down alert and up after 30 seconde and when i check the device it didn’t down.

I need your help.

run ping.php and see how long it takes to complete.

(and debug output of that command would be good if you want someone else to help you)