Yougov are the only major polling firm that stick SNP and Plaid together; the others have the two separate (and generally include the latter with the others)
The (worthless) internals on the poll have Labour ahead in Scotland ftr.
yougov internals are worse than useless, don't bother looking at them - especially the regional ones since they are tiny and unrepresentative - one of the other post-election polls that had Labour ahead nationally had the Tories at over 40% in Scotland which, eh, isn't the case.