Pypy3.9 scikit-learn problem

I created a pypy3.9 environment and did an install of

conda install -c conda-forge sympy

I also installed numpy, scipy, matplotlib, and scikit-learn with no errors.

If I try to import sklearn using pypy3.9, I get

Traceback (most recent call last):
  File "/home/doug/anaconda3/envs/pypy3.9/lib/pypy3.9/site-packages/sklearn/__check_build/", line 48, in <module>
    from ._check_build import check_build  # noqa
ModuleNotFoundError: No module named 'sklearn.__check_build._check_build'

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "", line 5, in <module>
    import sklearn
  File "/home/doug/anaconda3/envs/pypy3.9/lib/pypy3.9/site-packages/sklearn/", line 81, in <module>
    from . import __check_build  # noqa: F401
  File "/home/doug/anaconda3/envs/pypy3.9/lib/pypy3.9/site-packages/sklearn/__check_build/", line 50, in <module>
  File "/home/doug/anaconda3/envs/pypy3.9/lib/pypy3.9/site-packages/sklearn/__check_build/", line 31, in raise_build_error
    raise ImportError(
ImportError: No module named 'sklearn.__check_build._check_build'
Contents of /home/doug/anaconda3/envs/pypy3.9/lib/pypy3.9/site-packages/sklearn/__check_build:                       __pycache__
It seems that scikit-learn has not been built correctly.

If you have installed scikit-learn from source, please do not forget
to build the package before using it: run `python install` or
`make` in the source directory.

If you have used an installer, please check that it is suited for your
Python version, your operating system and your platform.
(pypy3.9) ~/python3$ 

Under the base environment, using python the runs fine.