## Issue
The scroll listener never unregisters, and is always registering itself on every scroll. I believe it was done that way to also handle the case of "element is already in viewport when mounted".
## Change
Tried to separate both "element is already in viewport when mounted" and "element scrolled into viewport" into different effects.
The timeout value used is a bit arbitrary, but is needed because the initial size is (0, 0), and to debounce any layout shifts. Reasoning: If an element is explicitly placed under this wrapper, the additional delay is acceptable since it's meant to be lazy-loaded anyway.
9745d6df3e