Not getting "ReasoningContentBlock" for bedrock claude models

[dastagirS]

im using anthropic.claude-sonnet-4-20250514-v1:0 (supports thinking/ reasoning) bedrock model in my strands agent. im using stream.async() for streaming text.

when using

            async for event in self.agent.stream_async(prompt):
                 if "data" in event:
                     yield event["data"]

i get the reasoning text with it. after checking the strands docs we get ReasoningContentBlock for reasoning text but i didnt see any in the stream event. and i only get data and delta which too only has text:"".

strands-agent -v : strands-agents==1.17.0