Hi! In order to deserialize bytes object, we use pickle.loads():

import pickle
import numpy as np
pickle.loads(np.float64(0.34103))

and the expected result is like below (because np.float64(0.34103) is not bytes objects, appropriate errors are expected)
---------------------------------------------------------------------------
UnpicklingError Traceback (most recent call last)
<ipython-input-19-5c07606a60f1> in <module>
----> 1 pickle.loads(np.float64(0.34103))

UnpicklingError: invalid load key, '\xc1'.


Here we have some questions that some numbers (it is rare) like 0.34104 prints the following result without errors.
pickle.loads(np.float64(0.34104))
=> True

This occurs only when the converted bytes start with b'\x88 (for example 0.04263, 0.08526, 0.11651 ...)
np.float64(0.34104).tobytes()
=> b'\x88.\xa8o\x99\xd3\xd5?'
Can anyone answer whether this issue is Python bugs?

Any answer will be highly appreciated.

Can anyone explain "pickle.loads(np.float64(0.34104))" prints "True"?

I explained this in https://bugs.python.org/issue42165#msg379755

This is not a bug in python, it's a bug in your code. You should not expect to unpickle something that wasn't created by pickling it.

Or stated differently: if you pass random byte strings to pickle.loads(), sometimes it might succeed and produce a random object because you've managed to create a valid pickle. But most often it will fail.