Extruder slamming into the print  

Extruder slamming into the print

I've been using the prusa mini for about two years and it's been perfect every time. After my previous print I noticed that the extruder went down to the bed level and to the back of the print area instead of up and to the right-hand side. 

I didn't think anything of it until my next print where I came back after the six hour print and noticed the extruder had gone to the same location, but this time there was finished print there so the extruder had burned a massive hole in my print.

Why is the extruder not going to the normal home position after printing????

G1 E-1 F2100 ; retract
{if max_layer_z < max_print_height}G1 Z{z_offset+min(max_layer_z+2, max_print_height)} F720 ; Move print head up{endif}
G1 X178 Y178 F4200 ; park print head
{if max_layer_z < max_print_height}G1 Z{z_offset+min(max_layer_z+30, max_print_height)} F720 ; Move print head further up{endif}
G4 ; wait
M104 S0 ; turn off temperature
M140 S0 ; turn off heatbed
M107 ; turn off fan
M221 S100 ; reset flow
M900 K0 ; reset LA
M84 ; disable motors