'NoneType' object cannot be interpreted as an integer

Previously (like yesterday) I was able to run dbt without any problem. I am using macOS Mojave 10.14.6. But after I upgraded to 0.19.1, somehow I can’t run any dbt command, except dbt debug.

For example, I run the following command:
dbt run -m MODEL_1 --profiles-dir ./profiles (I create a profiles.yml under profiles folder; which has been working all along)

I would get the following error.
Running with dbt=0.19.1
Encountered an error:
‘NoneType’ object cannot be interpreted as an integer

I also ran dbt debug --profiles-dir ./profiles, and it showed that
profiles.yml file [OK found and valid]
dbt_project.yml file [OK found and valid]

I am not sure what went wrong. Could anyone give any insight? Thank you!