Feeds automatically being marked read, even though they haven't been read

PLEASE READ THIS BEFORE POSTING: Read before posting / reporting bugs

Describe the problem you’re having:
If I’m in a category and I scroll down through the headlines, it is marking all of the articles as read, even though I haven’t opened any headers.

If possible include steps to reproduce the problem:
In combined mode, select a category with unread items. Scroll through the list of unread items. The items will get marked as read, even though you don’t open any of the articles.

tt-rss version (including git commit id):
v19.2 (e981d52)

Platform (i.e. Linux distro, PHP, PostgreSQL, etc) versions:
Ubuntu 18.04.2 LTS (GNU/Linux 4.4.0-141-generic x86_64)
postgres (PostgreSQL) 9.5.14
PHP 7.0.32

Browser is Chrome 73

Please provide any additional information below:
No custom themes, no plugins

Preferences > Mark read on scroll.

GAH. I didn’t realize I had turned that on. Thanks for the heads up.

that’s how this is supposed to work