Module:Cache vary request header "Origin" not defined

I got a few WordPress -sites running on a VPS with CentOS 8 + OLS.

After a closer look on my logfiles I noticed multiple entries similar to this:
2020-06-05 21:07:44.873828 [WARN] [] [Module:Cache] vary request header "Origin" not defined!

I am using the OpenLiteSpeed cache -plugin in WordPress with pretty much default settings.

Anyone able to enlighten me on what this warning might be?

Thank you.
I had the same issue - all WordPress REST API endpoints returned 500 as well.

I turned off "Cache REST API" in the Litespeed Cache Settings page and that seems to have resolved it.