Whats the crack

Was just wondering if I could ask if this crack is a concern. It seems to have been repaired with a relatively soft filler a bit similar to a test texture of mastic. i’ve been told it may be due to the house having had old wooden lentils that have now been replaced and filled use in packers which may have moved slightly? i’m not sure about the tiles on the roof either? Any help or guidance would be appreciated.