Credits spent on disabled builds

Hello,
in my repository settings, I’ve disabled “Build pushed branches” because I want to build only PRs.
However, I see that 80 credits have been spent building pushes into the “master” branch.
Here is the link to the repo:
https://travis-ci.com/github/js-tasks-ru/jsbasic-20210201_garlex/settings

I’ve also noticed that for some repositories this setting has been enabled during migration (not for this particular though, this has been initially created with this setting been disabled).