Disperancy in tvec outut for SolvePnP

Hello,
I have see some disperancy of output for SolvePnP. I am trying to get the tvec for a person face and for the same I have following model points
model_points_ref = np.array([
[-0.085, -0.02827123, -0.0114384], #–left ear
[0.085, -0.02827123, -0.0114384] , #–right ear
[ 0. , 0. , 0. ] , #–> nose tip
[ 0. , 0.08105961, -0.0325195 ] , #-- chin
[-0.05 , -0.0452415 , -0.06] , #-- left eye
[0.05 , -0.0452415 , -0.06] , #-- right eye
[-0.02847002 , 0.03331642 ,-0.03667993] , # – left mouth
[ 0.02847002 , 0.03331642, -0.03667993], # – right mouth
[-0.06, 0.02708319, -0.08046731], # – left cheek 3
[ 0.06, 0.02708319, -0.08046731], # – right cheek 13
[ -0.0383922, 0.06962711, -0.06106274], # – left jaw 6
[ 0.0383922, 0.06962711, -0.06106274]] # – right jaw 10
,dtype=np.float)

and when I give the following image points
image_points1 = np.array([[2101.97265625 , 663.4720459 ],
[2244.44726562 , 668.21960449],
[2177.18896484 , 695.39916992],
[2173.36547852 , 773.05883789],
[2133.6315918 , 658.98901367],
[2218.63525391 , 661.92834473],
[2149.75976562 , 727.35113525],
[2198.9987793 , 729.03833008],
[2110.0456543 , 717.19976807],
[2234.53735352 , 721.50158691],
[2136.87255859 , 759.55621338],
[2208.68237305 , 762.03759766]])
I get the correct tvec outout tvec1 = [[ 0.32085125],[-0.29647159],[ 2.44181232]] which matches with real world

Whereas when I give following image points
image_points2 = np.array([[2101.55297852 , 661.02923584],
[2244.66992188 , 666.83764648],
[2173.77758789 ,696.86071777],
[2169.9387207 , 774.43066406],
[2131.70605469 , 658.55169678],
[2216.97680664 ,662.11236572],
[2146.8059082 , 728.20385742],
[2195.95996094 , 730.30529785],
[2108.74438477 , 715.61627197],
[2233.9753418 , 720.90594482],
[2134.17773438 , 759.9309082 ],
[2206.14355469 , 762.98590088]])
I get the incorrect tvec outout tvec2 = [[-0.05087151], [ 0.04258687],[ 0.0451012 ]]

If you look at both the image points there is not much difference in pixel location but the output in both cases are different. I do not provide any initial values of rvec, tvec to solvepnp.

Kindly suggest what could be a possible issue.