Delay when creating new paragraph

[Daniel]

When I hit Return key (MacOS 10.15.2), there is a slight delay before a 
new paragraph is created. This is whith a rather complex document, 
multiple children, a lot of cross-references, bibliography, etc.

I seem not to remember this delay before 2.3.4. Did anyone else notice? 
If not, I could downgrade and try whether I see the same in 2.3.3.

Daniel