Real-Time Sync Requires Push Topics to be Enabled
For the real-time sync between FrontSpin and Salesforce to work properly (including real-time tasks notifications), Push Topics must be enabled for the admin user who linked their Salesforce admin account with FrontSpin (under SETTINGS => INTEGRATIONS => SYNC).
To check this in Salesforce, the admin user can go to SETUP => USERS => PROFILES (choose your user profile, e.g. System Administrator) then choose PUSH TOPICS and make sure all the checkboxes are checked.