This looks to be caused by streamable (again). Streamable was turned off on the Discourse onebox so you’d have to click the link a while ago but looks like it was turned back on for some reason. This service cannot seem to produce embeddable content and I encourage everyone to just stop using it. Upload your stuff to gfycat, youtube, or simply upload mp4 directly here.
In the case of the second example it does look broken on forum side, not sure what happened there. You can use devtools to open the video source and download the mp4 file if you really need to.
To fix the streamable issue, you can use devtools to produce the correct URL. https://streamable.com/IDhere
Curious, another option would be to upload the videos directly to the DevForum. Are the videos being referenced too large for our file size limits on the Devforum.
Are the videos being referenced too large for our file size limits on the Devforum?
I don’t know the size limit since I don’t think I’ve ever uploaded a video to the devforum, but the first one is 8.4 MB by downloading it in 720p. The second I’m unsure as it looks like it was directly uploaded (woops), and won’t download at all.