Scans with IN operator in the query predicate not using the secondary index

Setup :
1. 1-node cluster with data & analytics service
2. Default bucket loaded with cbworkloadgen data - 1000 docs.
3. Create an analytics dataset and secondary index -
create dataset default_ds on default
create index default_idx1 on default_ds(name:STRING, age:BIGINT)
4. Connect link Local
5. Run query -
select * from default_ds where age=70 and name in ["pymc171","pymc272"]
6. Check the plan - default_idx1 should be used in the plan

With 6.0.4, default_idx1 is used. But in 6.5.1-6298, default_idx1 is not used. Results are the same in both. Attached are the execution plans from 6.0.4 & 6.5.1.