Seems like it’s still a thing, where if the delay between the message and the timeout is really low, it won’t <message deleted> it.
I noticed this today, with Moobot only sending a single timeout for the !seppuku command: Imgur: The magic of the Internet
A artificial delay server-side on my end is pretty much out of the question, as that makes a lot of spam appear for a split moment. People not being able to see the spam is the biggest point of spam filters.