so i have listed down the current issues in the following manner
query1 - without LIMIT - this FAILS with timeout
query 2 - query1 with LIMIT - this PASSES
query 3 - which we found yesterday, this FAILS with timeout both with and without LIMIT. i am assuming this is an empty result set case
for all these cases i have found the equivalent queries in wikipedia datasource and tested and got similiar results and have raised in github. please refer the github issue for more details