Google events and TIMIFY bookings sync both ways without any trouble, as long as the events and bookings don't take place at the same time, or overlap each other.
For example, say you have a 10:00 meeting in your TIMIFY Calendar, and an event gets made in your Google Calendar for the same time. This is detected as a scheduling conflict, and will get flagged in the "Sync Conflicts" tab in your app. To resolve the conflict, you have to delete or move one of the bookings.
Working Time Conflicts
Say you define a resource's working time as 8:00 - 17:00 - and restrict them from accepting appointments outside their working times - if a Google event is made in that resource's Google calendar outside this time frame, say at 17:30, the event will not sync to your TIMIFY Calendar.
If you make a booking for the same TIMIFY resource at say 12:30, and they move the booking to 17:30 in their Google Calendar - which is outside their working times, this change will not be synced to TIMIFY. The meeting will remain in your TIMIFY Calendar for 12:30, and display in Google for 18:30.