FYI, HSEARCH-4303 was fixed in 6.1.0.Alpha1, released last Friday. Maybe you could give it a try?
I’ll backport the fix to 6.0, but I’d like to confirm that it works for you first, and perhaps address other problems (e.g. HS6 corrupting index after merge of detached entity with @OneToMany association - #6 by busitech).
6.1.0.Alpha1 release announcement: Hibernate Search 6.1.0.Alpha1 is out, now with asynchronous, distributed automatic indexing! - In Relation To