Quotation marks and other symbols, when typed in the title of a spoiler tag, show up as broken HTML entities.
This only happens on the normal website. Other Lemmy UIs (Tesseract, old-reddit style, Photon, Alexandrite) are not affected.
Examples of characters:
"
becomes "
&
becomes &
<
becomes <
>
becomes >
Example occurrence:
quote, ampersand, less than, greater than " & < >
Expected correct result: " & < >
Expected erroneous result: " & < >
Warning: The following spoilers contain full-page screenshots of the phenomenon in question. Do not open on a slow or metered connection.
Normal website section.
On sh.itjust.works:

On lemmy.world:

On lemmy.blahaj.zone:

On lemmy.dbzer0.com:
Alternative UI section.
On sh.itjust.works, Tesseract version:

On lemmy.world, old-reddit style version:

On lemmy.world, Photon version:

On lemmy.world, Alexandrite version: