TOC does not render all headings?

[rodhash]

When opening TOC pane it shows everything just fine but as soon as I start scrolling up or down, I see asterisks instead of my heading icons:

This only happens when scrolling up/down on big .norg files .. on small ones I didn't notice this issue.

Is this actually an issue?

Or perhaps is this an expected behavior with specific settings (which I didn't find) where I can specify how many lines TOC should render?