Screenshot
Table cell templates are editable, but their re-rendering is broken.
Example: try modifying any of the table cell templates at https://nl.wikipedia.org/wiki/Gebruiker:Ad_Huikeshoven/jh?uselang=en&veaction=edit#Prestatietabel
They can be edited, such an edit can be saved and results in correct wikitext, but is rendered broken (the markup is rendered as text, instead of creating a table cell).
(Found when playing with bug 67850.)
Version: unspecified
Severity: normal
URL: https://nl.wikipedia.org/wiki/Gebruiker:Ad_Huikeshoven/jh?uselang=en&veaction=edit#Prestatietabel
Attached: