Sorry for mixing two or more things that might be unrelated. I was trying to debug a report that hit higlighting isn't working on DSpace 4 when I noticed that search results don't show abstracts (on demo, I haven't seen a single one; on my test server running master it's even weirder - an empty query will yield abstracts, a non-empty query will yield results without abstracts).
Searching for author names doesn't highlight the name. It is configured to work with dc.contributor.author.
Both abstracts and hit hl (for abstracts and authors) work on my DSpace 3 instance.
This might be unrelated to the problem: In addition, I noticed that on demo all items I looked at have dc.creator filled in, with only some having dc.contributor.author filled in in addition. I'm wondering how these items were created when submission forms produce dc.contributor.author.