**List of steps to reproduce** (step by step, including full links if applicable):
Run this on https://commons.wikimedia.beta.wmflabs.org/wiki/:
```
var api = new mw.Api();
api.postWithEditToken( {
format: 'json', title: 'User_talk:AJ-test', action: 'edit', summary: 'test3', text: 'baserevid 258476 again', baserevid: 258476, section: 2
} ).done( function ( data ) {
} );
```
**What happens?**:
```
{"edit":{"result":"Success","pageid":104974,"title":"User talk:AJ-test","contentmodel":"wikitext","nochange":"","watched":""}}
```
But no actual edit has been made. Also note the absence of edit.newtimestamp.
**What should have happened instead?**:
Edit conflict or error about invalid baserevid. Using an obviously wrong baserevid like "2" yields the same result.
Using a "good" baserevid results in the edit being made as expected, it's just the response when triggering an edit conflict or using an invalid baserevid that's bad.