Auto embedded videos do not show up in feed due to missing protocol

Hi,
I embed e.g. Vimeo-Videos by pasting an URL like

into my post. That gets transformed into an embedded video as expected.

BUT: In my RSS-feed it does not work, as the iFrame’s URL reads

//player.vimeo.com/video/78150218

instead of

https://player.vimeo.com/video/78150218

.

Example:
Post https://blog.crusy.net/2014/01/30/the-touch-board/
Feed https://blog.crusy.net/feed/

My feed reader (Fever) interprets this as a local URL to my blog, which leads to a 404. BTW: I see this a lot, even on other blogs and/or previous versions of wordpress