Bugzilla

I was able to reproduce it. See bug 1789793

@Spero: If you want to manually narrow down your problem, this is what I did:
- Export the address book as VCARD/.vcf
- Import it into a new seperate adress book
- Make sure you work in the new/backup adress book!!
- Delete contacts until the search function works again. This will help you find the problem.

In detail:
- Delete all contacts that start with "a". Then try to search.
- If it doesn't work, delete all contacts with "b". Try search again.
- Delete "c" ...
- Repeat until the search works. Remember the respective letter.
- Delete all contacts and import again.
- Start with deleting single contacts that start with the letter. Continue until search works.
- Check the problematic contact in the .vcf file for any weird entries.

Of cause you may have more than one "corrupted" entry.