Lathe Machine Motorized tool problem CMZ

Hi everyone,
I'm having a trouble with a new lathe machine in a drilling operation.
1st i make turning, and after i drill 2 holes (pre-finishing + finishing)
I don't know how but sometimes during Masspro, the pre-finishing loses positioning orientation and make the hole in another position. But finishing always ok!!.
Some advice?
The prefinishing is below

(...)
N40(DRILL-pre-fini)
T0505
G55
M5
M8
M468
M80
G28H0.
G0C347.0C346.9
G98G97F80M83S4000
M18
G99G55G0X95.0Z5.0
Z-53.0
G83Z-64.30F0.25
G80
G0Z-53.0
G0C164.0C163.9
G83Z-64.30F0.25
G80
G0Z-53.0

G53Z120.0
M1

N50(DRILL-finish)
T0909
M80
G28H0.
G0C347.0C346.9
M8
G98G97F80M83S2000
M18
G99G55G0X95.0Z5.0
Z-53.0
G1Z-63.21F0.30
G4U0.2
G80
G0Z-53.0
G0C164.0C163.9
G1Z-63.21
G4U0.2
G0Z-53.0
G0Z10.0
M80
G0C360.0