This came from the VisualEditor feedback page in Hebrew. I couldn't replicate, but the problem is evident in this diff:
The user only changed the link at line 20 (blue, left) but VE seemed to have injected a bunch of wikitext into the template box above.
Version: unspecified
Severity: normal
| Status | Subtype | Assigned | Task | ||
|---|---|---|---|---|---|
| Resolved | Jdforrester-WMF | T53792 VisualEditor: Non-English Wikipedia issues (tracking) | |||
| Resolved | Krinkle | T52684 Template auto-filled with wikitext on edit |
I couldnt reproduce it on
https://he.wikipedia.org/wiki/User:John_Vandenberg/test
I cant find any bug for visualeditor dumping in a subst:ed copy of a template. Very strange.
After talking to gwicke, this seems to be a temporary bug either related to some caching problem or an issue that was resolved, since it cannot be replicated and a lot of other updates were done that fixed related problems.
Closed as likely fixed.