The decryption results are inconsistent when great different parameters are used

Description

The result of following code is different when choose different params coeff_mod_bit_sizes

import numpy as np
import tenseal as ts
num = 2048
np.random.seed(100)
g = np.random.random([num])
np.random.seed(101)
h = np.random.random([num])
context = ts.context(
            ts.SCHEME_TYPE.CKKS,
            poly_modulus_degree=4096,
            coeff_mod_bit_sizes=[40,28,40]
          )
context.generate_galois_keys()
context.global_scale = 2**28
enc_wx = ts.ckks_vector(context,h*0.25)
enc_forward = ts.ckks_vector(context,g)
res = (enc_forward*enc_wx).sum()
print("true result:",(num*np.log(2)+(g*h*0.25).sum())/num)
print("decrypt first, and then add num:",np.log(2)+res.decrypt()[0]/num)
print("add num first ,and then decrypt:",(num*np.log(2)+res).decrypt()[0]/num)

reslut:
true result: 0.7536323584203359
decrypt first, and then add num: 0.7536461963235349
add num first ,and then decrypt: 0.7536461963237073

While when I change the coeff_mod_bit_sizes even a little, the result is incorrect(seeing add num first ,and then decrypt result). And it has nothing to do with random number seeds

context = ts.context(
            ts.SCHEME_TYPE.CKKS,
            poly_modulus_degree=4096,
            coeff_mod_bit_sizes=[40,29,40]
          )
context.generate_galois_keys()
context.global_scale = 2**29

reslut:
true result: 0.7536323584203359
decrypt first, and then add num: 0.7536386286083517
add num first ,and then decrypt: -0.24636115532554803

How to Reproduce

Run the above code directly

Expected Behavior

A clear and concise description of what you expected to happen.

Screenshots

System Information

• OS: [Windows]
• OS Version: [10]
• Language Version: [e.g. Python 3.7]
• Package Manager Version: [tenseal 0.3.4]

Additional Context

I wonder why did this happen and how to choose parameters correctly

Run the provided Python reproduction with both coeff_mod_bit_sizes configurations, starting at ts.context, context.global_scale, and ts.ckks_vector operations. Trace how the CKKS context and the res.decrypt() path handle the parameter changes. Done means the behavior is explained and, if it is a bug, the inconsistent result is corrected or clearly documented.