what triggers the deletion of history record?

[tenge-amzn]

Sometimes it just doesn't delete the history of listed domains..

[NA0341]

I don't think that it deletes history entries - but rather prevents them from being created in the first place.
As it says: Any URL that matches any entry will be prevented from entering your browser history.

As to why the extension doesn't work as expected: provide the following info so the dev can help you:

• Your OS & Version
• Your Browser & Version
• Any unusual things or customizations about your system or browser

I'm using Vivaldi on Manjaro Linux and it works perfectly fine for me.
I have currently 70 filter entries.