Symbol lookup doesn't work for preference shares

[olsh]

Symbol Lookup doesn't work for some Russian preference shares.

There are two shares: RU0009029540 - SBER - ordinary shares RU0009029557 - SBERP - preference shares

https://finnhub.io/api/v1/search?q=RU0009029540&token= - this query works as expected https://finnhub.io/api/v1/search?q=RU0009029557&token= - this query doesn't work

The same issue can be reproduced for shares BANE/BANEP, TATN/TATNP