There’s currently an issue where highlighting text that includes spoiler text doesn’t actually put the spoiler tags in the quote. This definitely used to work, but I’m not sure when it broke.
For example, if you highlight this entire sentence, the spoiler part isn’t behind spoiler tags in the quote.
As far as I know the select text and quote feature will do a best effort work trying to preserve formatting using our HTML->Markdown conversion library.
If you use the quote full post (first button in the composer) we go to the server and ask for the raw markdown, and then the quote contains all the original formatting.
Support for quoting spoiler text was added back in August 2018 and it was improved in June of this year (even if incidentally) as referenced here. So while I understand that I can do the full post quote as a workaround, it remains that this is functionality that used to work and is now broken.
Any chance this will be fixed?
Probably eventually, for now you can make the necessary edits in quotes, so there is a workaround.
Okay. Just wanted some kind of confirmation, so thanks.
I just realized this is still broken. 
