I'm seeing a similar failure on a debug build of 3.10 as well.

./python 
Python 3.10.0+ (heads/3.10:9e7a2e4920, Nov 22 2021, 10:51:32) [GCC 9.3.0] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> async def f():
...     pass
... 
>>> coro = f()
>>> frame = coro.cr_frame
>>> frame.clear()
<stdin>:1: RuntimeWarning: coroutine 'f' was never awaited
RuntimeWarning: Enable tracemalloc to get the object allocation traceback
python: Objects/frameobject.c:695: frame_clear: Assertion `f->f_gen == NULL' failed.
Aborted (core dumped)


I don't know why that assertion is there, it doesn't seem to be valid.