Android fail to read screen timeout

I use Motion Detector & Tasker to turn screen on. It works OK ... like this: - when screen is off and Motion Detector discovers a motion it will turn screen on. - Tasker sets display timeout to 30 sec Here is where it goes wrong ... the screen is not turn off after 30 sec but after 6-8 sec ... but when I tap the screen when it is turned on then it stays alive 30 sec. I seems that Android can't read the timeout in Display settings which is 30 sec ... only when I tap the screen it reads the settings. I have Android 9 & Galaxy Tab S5e. Then I took another approach .... I installed SETEDIT from Play to check the value of 'screen_off_timeout'. Then I ran two different test - one with Tasker disabled - one with Tasker enabled. Taker disabled: 1. In 'Settings/Dislay/Screen timeout' I set to 15 sec 2. The display shutdown occured after 15 sec first time ... OK 3. When I woke the display its shutdown occured after 15 sec ... OK 4. In SETEDIT the value of 'screen_off_timeout' was 15000 ms = 15 sec 5. In 'Settings/Dislay/Screen timeout' was still 15 sec So it seems that without Tasker it behaves as expected. Taker enabled: 1. In 'Settings/Dislay/Screen timeout' I set to 15 sec 2. In Tasker I set 'Display Timeout' to 1 min 2. The display shutdown occured after 15 sec first time ... OK 3. When the display woke up due to a motion was detected ... its shutdown occured after 5-7 sec ... not OK 4. In SETEDIT the value of 'screen_off_timeout' was changed by Tasker to 60000 ms = 1 min ... OK 5. In 'Settings/Dislay/Screen timeout' was also changed to 1 min ... OK So both SETEDIT & 'Settings/Dislay/Screen timeout' shows the correct values ... why is screen shut down after 5-7 sec???