Index Scan fails for filters on expressions of type Timestamp With Local Time Zone

Problem
Index Scan fails for filters on expressions of type Timestamp With Local Time Zone.

create schema support4130;
-- 1. create a table that is large enough for not being replicated
create table g as (values 1,2,3,4,5,6,7,8,9,10 as t(x));
create table tt as select trunc(to_timestamp(current_timestamp))+rownum-1 ts from (select 1 a from g,g,g,g,g,g);
 
-- there should be no index on the table tt
select * from EXA_USER_INDICES where INDEX_SCHEMA='SUPPORT4130';

-- and this should work:
select * from tt where ts = trunc(current_timestamp);

-- after performing a join:
select * from tt a join tt b on a.ts = b.ts;

-- an index has been created:
select * from EXA_USER_INDICES where INDEX_SCHEMA='SUPPORT4130';

-- now it crashes
select * from tt where ts = trunc(current_timestamp);

Workaround
Use cast to timestamp

select * from tt where ts = to_timestamp(trunc(current_timestamp));