Error message with manual spoiler tags

[Seiyashi 4,097]

I'm attempting to input text with very heavy usage of the manual spoiler tag ("["spoiler"]" and ["/spoiler"]), but I can only get it to work with one spoiler tag. The second in the post doesn't show up, and once there's three in one attempted submission, I get this error message:

[[Template forums/front/topics/topic is throwing an error. This theme may be out of date. Run the support tool in the AdminCP to restore the default theme.]]

Have I broken something by accident?

EDIT: turns out that leaving a newline between the end of a spoiler tag and the next non-spoilered line works. Leaving this post here for posterity in case anyone else runs into the same issue.

Edited August 9, 2021 by Seiyashi