Disable "animation" thumbnails with stacked frames

The normal thumbnail is fine, but mine is also pulling down a super tall thumbnail which is 60 frames stacked, which once it’s cached is fine, but initial generation takes 5-10 seconds, and I don’t need it.

Unsure how to change the poster variable so as to exclude it, as I don’t actively request this thumbnail, it just gets something like this tacked onto the end of the request:

?time=0.000s&duration=6.000s&height=108&imageCount=60

Result:

(can’t edit?)

Update: turns out this thumbnail is what’s used to show the preview when you hover over the timeline. I guess I was hovering before the vid started rendering - which then triggers a call to the server to generate this image, which makes a 5-10 second delay.

Will have to test more to see if this is an issue.