Are collective nouns always singular on GMAT?
or
Can we treat them as singular if they refer to individuals of a collection.

e.g.,
The committee was divided in its opinions
vs
The committee were divided in their opinions.


Further, somewhere I read sometime back that the usage should be consistent in the sentence. But there can arise a need to use different forms. e.g.,

The committee has issued a report but they were divided in their opinions.

Is the above sentence correct or it goes against the consistency principle.