We haven't identified the issue with constrained delegation and MSAS yet.
Our product doesn't report any errors but it acts as if the service account is not delegated and fails SSO once you set the account to constrained
Now what you can do is use 2 service accounts, 1 for vintela (global.properties idm.princ) set to constrained and one for the CMS set to unconstrained to allow SSO2DB to keep working.
Best I can offer in the near future. We have develoeprs looking into the cause but so far it has eluded us on the MSAS thing.
Regards,
Tim