Hashing error in experimental_memo(), but not cache()

Getting the following error, but the type referenced is clearly hashable (and works with cache()):

UnhashableParamError : Cannot hash argument ‘drill_type’ (of type utils.ISF_Functions.DrillingType ) in ‘split_forecast_by_commodity’.

Function def:

@st.experimental_memo(ttl=CACHE_LENGTH)  # 12 hours
def split_forecast_by_commodity(pra_id: id, drill_type: DrillingType) -> tuple[dict[str, pd.DataFrame], dict[str, pd.DataFrame], dict[str, pd.DataFrame], dict[str, pd.DataFrame], pd.DataFrame]:

param type def:

class DrillingType(enum.Enum):
    Horizontal = 1
    Vertical = 2

ST 1.4
python 3.9
windows 10

Hi @apassy :wave:

This is a known, confirmed bug with st.experimental memo():

I would also upvote this issue to show to your interest: