Hi Vaibhav,
Not all methods will be shown in even full graph when methods are taken less than 10 ms and we understood the target exit calls are not under "async activity" in call graph and regarding your query on what is wait it could be that thread is in waiting for some other resource as such
But to confirm if any other packages are part of package excludes, Can you click link "packages excluded from the call graph" which will be at bottom of the call graph screen and force those packaes in includes and see if you get more visibility for new snapshots?
Regards,
Arun