Your documentation states that a Call has a 1:n relationship with Sessions (ER Model diagram here: https://docs.microsoft.com/en-gb/graph/api/resources/callrecords-api-overview?view=graph-rest-1.0)
It also states that a SessionID uniquely identifies a session. (https://docs.microsoft.com/en-gb/graph/api/resources/callrecords-session?view=graph-rest-1.0)
This does not appear to be the case.
The image below shows JSON snippets of two calls, each containing the same SessionID. The relationship is therefore m:n. The key is therefore the compound of (CallID, SessionID).
Can you confirm that this is correct and your documentation is wrong?


