It’s a good guess, but because of these sd-Card problems I have replaced it with an ssd more than 2 years ago. 
Maybe a complete new installation would help, but I don’t have time to bring oh up to speed again with all the settings.
Maybe when 2.5 stable is released…
I had exactly the same issue with OH 3.0.1. It turned out that an obsolete item was referenced in a trendItem definition in:
/var/lib/openhab/jsondb/uicomponents_ui_page.json
Editing that reference solved the issue.
Hi Hans,
Welcome to the community and thanks for your response.
Actually I am on 3.0.1 as well and I am very happy with it.
Enjoy the community and openHAB of course.