A community member encountered an error when using index.as_query_engine on a SummaryIndex with LlamaIndex version 0.8.59. Another community member tried to reproduce the issue but was unable to do so after reinstalling the same version. The original poster acknowledged the feedback, indicating that as long as the issue is resolved, it is not a major concern.
Separate issue, with LlamaIndex 0.8.59 I got an error about instantiating a retriever with an abstract method when doing index.as_query_engine on a SummaryIndex.
