[Stock MM] Lock screen doesn't lock when screen off

im using T-Mobile Galaxy S5 (SM-G900T)
When i turn screen off (to lock phone), it doesnt lock, it shows a lock icon at the bottom which i have to swipe manually to lock phone

NOTE: all lock options are working, and the point is not here, the point is that phone doesn't lock automatically after 5s screen off/after power button click

can someone help please?

info:
-Stock MM 6.0.1
-T-Mobile (SM-G900T)
-lock options working (including fingerprint)

Screenshot: (attached)

Attached Thumbnails