Steps to Reproduce:

1. Turn on live preview (“Show previews without reloading the page” at Preferences / Editing) and VideoJS beta feature.
2. Edit a random page and insert a video embed, say, [[File:Rudy Mancuso & Maia Mitchell - Magic (Official Music Video).webm|1000px]].
3. Press the preview button.
4. Change the display size to e.g. 100px.
5. Press the preview button again.

Actual Results:
The JavaScript-less experience (native HTML5 player) displays in the right size (100px), but the VideoJS player appearing soon after uses the size of the first preview (1000px). This remains so even if the video is replaced, only the ordinal within page counts.

Expected Results:
The VideoJS player uses the size specified in wikitext, just like the native player.