Submitted by: @hvlad

Relate to CORE1006

create table T (
ID integer not null,
N1 blob sub_type 1 segment size 80,
N2 varchar(10)
);
commit;

insert into T (ID, N1, N2) values (1, 'www', 'qwer');
commit;

alter table T add constraint PK_T primary key (ID);
create index T_IDX on T computed by (cast(substring(N1 from 1 for 100) as varchar(100)));
commit;

update T set T.N2 = 'asdf' where http://T.ID = 1;
commit; -- AV here

Commits: f4f2861 2541b58 bd1ea8b c747acb FirebirdSQL/fbt-repository@7b5a11b FirebirdSQL/fbt-repository@036eea6