What is the bug?
OpenSearch 2.5 fix the wildcard query case insensitive bug. More reading at opensearch-project/OpenSearch#5515.

Currently, SQL engine

• when rewrite Like operator as wildcard query, use default setting case-insensitive = false.
• when compile Like operator as Pattern, use default setting case-insensitive = false.

Because of the bug, Like operators works in 2.4, e.g. value = Amber, pattern = Ambe?

• As DSL query, Standard Analyzer uses the lowercase token filter index Amber as amber. Pattern Ambe? should not match amber, but with wildcard query bug, it matched.
• In memory processing read source doc without lowercase token filter, the value is Amber, pattern Ambe? matched as expected.

What is the expected behavior?
I suggested to change LIKE using case-insensitive = true by default.

• which is actually OpenSearch 2.4 behaviour, it is not an breaking change.
• In MySQL, SQL patterns are case-insensitive by default..
• If user want case sensitive, use wildcard query instead.