Oneboxes duplication when you type in the composer

Having a onebox and typing characters duplicates oneboxes, and also their icon if they have one.

It happens for various domains, it’s not related to Wikipedia oneboxes.

Steps to repro:

  1. Paste a link that generates a onebox

  2. Type some text in the composer

  3. Observe :dancing_men:

It’s likely related to a recent commit, as it doesn’t happen on my test instance 3.1.0.beta5 (78d8bd7c81).