Yup. Google map has no problem for locking GPS but it guided me before to a kelapa sawit farm and I was like WTF? 
Not really that case bro. I clicked waze and waited endlessly to detect my current location let alone my destination........Thanks to that WAZE lock in problem I almost ended in Genting Highlands for no particular reason!  :confused:

My dotter Redmi Note 3 having no problem. Like your case maybe becoz of Android problem? Old Android probably working well. Will there be any gps fixes from Android in the future? I don't know about flashing ROM.

Anyway to lock in GPS under 30 seconds and 10 seconds outdoor is acceptable. However is there other phone models quicker than that?   

Frustrated becoz of this GPS problem until I'm considering back to square one brand Samsung......