The FBI does not have much reason to disclose relevant information about it's sources and methods, so we can't easily measure to what extent this particular task force (or any other unit of the federal US intelligence community) surveils social media.
But as an academic handbook puts it:
Social media intelligence (SOCMINT) is an increasingly important component of digital intelligence, itself now a major source of information for police, security and intelligence authorities on the identities, location, movement, financing and intentions of their suspects.
Here is a relevant article from the ACLU which attempts to monitor such activities through Freedom of Information requests and the like. It argues:
Based on what little information is publicly available, it’s clear that the federal government routinely tracks domestic social media users, with a particular focus on immigrants.
Most of the specific instances that article mentions are related to other agencies, not the FBI. I haven't yet seen any significant statement from the ACLU about this Task Force in particular.
The big NSA leaks back in 2013 first revealed that the FBI's Data Intercept Technology Unit, or DITU already at that time had significant technical infrastructure for large-scale and open-ensed surveillance of social media.
In March of this year, a San Diego news outlet uncovered Operation Secure Line which involved social media surveillance and included participation by the FBI. Again this was not necessarily linked to that Task Force in particular, about which very little of substance is in the public record.