Unwanted brush strokes on replayed action

I've requested access to the file

OK, here ya go:

https://drive.google.com/file/d/1vrxlb7yf4bmFFo6EDPwd_lpYoII1wYDy/view?usp=sharing

I don't really have a ready space for folks to upload to. Maybe this is something that can be done with some solutions? Normally, I would expect that you put the file on something like Google Drive or DropBox or a similar service and share a link.

The Reply box doesn't provide a way to add attachments, other than photos or videos (despite this instruction set: https://community.adobe.com/t5/using-the-community-discussions/community-how-to-guide-tips-amp-best-practices/m-p/11601738#M47075:~:text=To%20add%20any%20documents%2C%20pdfs%2C%20and%20similar%20you%20can%20use%20the%20attachment%20tool%20situated%20at%20the%20bottom%20of%20the%20post/reply%20box.)

The Saved Action is a .atn file. Can you provide an upload link?

I'm not seeing the same behavior on my end. I'm using a Wacom tablet though, so maybe it has something to do with the input. Can you export your action and share it? Just put the one action into a new Set and use Save Action from the panel menu. 

Update: I can get rid of the blob artifact by disabling Size Control via Pen Pressure in the Brush Settings (and making sure "Always use Pressure for Size" is disabled), but this results in brush strokes with no width variation.