https://en.wikipedia.org/wiki/Special:AbuseLog/14846961 and https://en.wikipedia.org/wiki/Special:AbuseLog/15158997 both appear to show removal of speedy deletion templates, but clicking through to the real diff shows that neither edit removed a speedy deletion template.

Since both edits are very close (2 lines away) from the *previous* edit's content, I suspect that this bug is related to handling of edit conflicts; e.g. Alice and Bob both open Article; Alice adds {{db}} to the top of the article and saves; Bob changes some content on the second line and tries to save, receives an edit conflict notification, and successfully merges his edits in with the net result of keeping both the {{db}} and the edits on the now-third line. AbuseFilter diffs the changes after Alice's edit and after Bob's edit *pre-merge*, resulting in the apparent loss of {{db}}.