python – ‘conda activate’ not actually activating a virtual env

I’m having a problem that conda activate would never actually activate the virtual environment and looking for a solution to fix it.
It happens like this:

$conda --version
conda 4.13.0
$conda info -e 
  base   *  C:\Users\hoge\anaconda3 
  py38      C:\Users\hoge\anaconda3\envs\py38 
$conda activate py38
$conda info -e  
  base   *  C:\Users\hoge\anaconda3 
  py38      C:\Users\hoge\anaconda3\envs\py38 

I’ve heard that conda install -n root -c pscondaenvs pscondaenvs would fix this and tried it, but it never caused any difference.
(c.f. github.com/conda/conda/issues/626#issuecomment-313913036)

Does anyone know how to solve the problem? Thanks