Hello :)
When things don't go as supposed i have a personnal solution, that probably somebody will come with better elegant, but mine work well and it's bullet proof :)
The trigger of new mail arrive is a power automate one, since you lost the body inside what if , when in the power automate you store it inside a sharepoint list.
Then creat a topic to read it from the list
Then in the prompt part use instruction and say when a mail arrive please use this topic with the "/" action ?
It's not the most elegant or quick but it's bullet proof :)
In real life i use this method with autonomous agent link to Support Email, wich take body, attachment, and collect information, store it inside a sharepoint list. Then the Agent is doing AI magic to enrich the content en prépare an answer to be review by support team based on KB of the company and inserted in the Support internal tool.
if this helped you, please check the answer button, it's important for the community and search engine :)