Firefox has quirky copy/paste image behavior

I think something here is still broken, even within Discourse.

there is a .webp image in this post;

the full URL to the image is here, so its hosted on Discourse; https://d11a6trkgmumsb.cloudfront.net/original/4X/4/7/3/473600457bad5d0f8eb85689b40ca13507fac2bc.webp

note that this is an animated .webp image

However when I right click on the image in the Discourse page and Copy, then Paste into the onebox, I instead get a PNG which then gets converted by Discourse into the following JPG;

image

any thoughts? I am guessing this is not the intended behavior either?