While reading an answer over on Puzzling.SE, I noticed that having a spoiler in a list hides the item number/bullet. I can demonstrate it here. (It seems to be an issue only in Chrome.)
Ordered lists.
This is a spoiler in a list. You can't see the number unless you hover the spoiler.
- Numbering continues as expected.
The issue can be reproduced multiple times in a single list.
It even holds when a list item consists of multiple paragraphs.
Unordered lists.
- The issue holds in unordered lists as well.
This can be seen here.
The number/bullet is not hidden when the spoiler is not the first part of the list item.
See?