Correcting a video block that has reformatted itself incorrectly!

Site URL: https://meditateinthewestmidlands.co.uk

We have a live-stream page for meditation classes.  These are recorded and put up for people to view during the week after the class.  When the video & thumbnail are added to the video block the video box often changes format and the thumbnail gets cropped so the text can't be read properly.  Is there something that can be done to fix this?  We've tried adding a new block, & adding the link & thumbnail again.  Sometimes this works but more often it doesn't!  Any help would be appreciated, thank you.

This is a link to a page with a video block that is formatted correctly; https://www.meditateinthewestmidlands.co.uk/stream/cp14

This is a link to a page where its gone horribly wrong!! https://www.meditateinthewestmidlands.co.uk/stream/cp24

This seems to have righted itself.  We're wondering if there's anything that can be done to fix it when it happens again or prevent it happening?  Any advice would be welcome.  Thank you.