PyCharm Debugger fails for Python 3.8

I can run a new Python 3.8 project within PyCharm fine, but when I try to debug I get:

C:\Users\cpurtill\venv3\Scripts\python.exe "C:\Program Files\JetBrains\PyCharm Community Edition 2019.3.3\plugins\python-ce\helpers\pydev\pydevd.py" --multiproc --qt-support=auto --client 127.0.0.1 --port 59934 --file C:/Users/cpurtill/Documents/Dropbox/Python/expenses/expenses.py
Traceback (most recent call last):
File "C:\Program Files\JetBrains\PyCharm Community Edition 2019.3.3\plugins\python-ce\helpers\pydev\pydevd.py", line 25, in <module>
from _pydev_bundle import pydev_imports, pydev_log
File "C:\Program Files\JetBrains\PyCharm Community Edition 2019.3.3\plugins\python-ce\helpers\pydev\_pydev_bundle\pydev_imports.py", line 9, in <module>
import xmlrpclib
File "C:\Python27\Lib\xmlrpclib.py", line 194
MAXINT = 2L**31-1
^
SyntaxError: invalid syntax

Process finished with exit code 1

C:\Python27 is obviously Python 2.7, but I can't see why it's being pulled in - it's not in the Project Interpreter paths for this project.

I can run and debug Python 2.7 fine. I'm running on Windows 8.1 Pro with:

PyCharm 2019.3.3 (Community Edition)
Build #PC-193.6494.30, built on February 6, 2020
Runtime version: 11.0.5+10-b520.38 amd64
VM: OpenJDK 64-Bit Server VM by JetBrains s.r.o
Windows 8.1 6.3
GC: ParNew, ConcurrentMarkSweep
Memory: 1965M
Cores: 8
Registry:
Non-Bundled Plugins:

Thanks for any ideas!