VL53L4CD short range issue with high reflectance metal target

[abasty]

Hi,
I'm working on a tool that must be armed only in a proximity range of 0-5mm with different target materials.
The sensor has a protection glass(1mm thickness) 3mm away so the real distance 0mm of the reported measures starts at 4mm from sensor.
I had chosen the VL53L4CD for its precision in range 1-200mm but, with metal target (grey and reflecting), but I measure those values:

Real distance from glass[mm]      Measured distance[mm]
0                                                   18
5                                                    6
10                                                  1
15                                                   4
20                                                   18
25                                                   25

There is a non-linearity in the distances that i want to consider to arm my instrument and also without the glass the behaviour persist..
With other target materials as paper, black target, white target, teflon etc. there aren't non-linearity.
I'm using standard API with VL53L4CD_PROFILE_CONTINUOUS and TIME_BUDGET = 15ms.

Could you give me some suggestions?
Thanks for your time,
Andrea