Since yesterdays update to 4.5.3 linebreaks are ignored in Posts (classical editor). Like here https://www.oberton.org/en/hearing-test-saus/
The problem doesn’t exist anymore… don’t know the reason. I deactivated and reactivated Classic Editor plugin. One other thing I did was switching off google maps in The Event Calendar, shouldn’t be related. It’s not reproducable. So, you may delete this topic.