We had several webhooks configured to only fire on specific transitions to the Jira Server connector in Teams, and that relied on a Atlassian provided translator at https://connectors.msteams-atlassian.com/JiraServer
The new Jira Cloud connector is successfully displaying messages from issue related events, but it won't display anything from a transition event.
I captured the webhook data from a transition event, and sent it to Teams, and got a 400 response: "Webhook Bad Request - null or empty eventType"
Hopefully this gets the attention of someone on the product team, support has not been helpful.