Steps to reproduce: Open the wiki editor and enable syntax highlighting. Declare a reference with a name containing a slash, like <ref name="1/2">Book by Author, page NaN</ref>. Use it in a template parameter like |param1=text1<ref name="1/2"/>, then close the template and continue the page prose. Include another reference like <ref>yeah, more sources</ref> and some more text after it.
Expected result: The whole template should be highlighted in the violet font, the prose text should not be highlighted.
Actual result: The template is highlighted correctly until the problematic reference is called, the rest of the template syntax appears to be recognised as if it was part of the reference. The prose text after the second reference is highlighted as if it was part of the template, even though the template is already closed.
(encountered at https://en.wikipedia.org/w/index.php?title=Daimler_Regency&action=edit, see https://test.wikipedia.org/wiki/T270880 for a minimal example)