How to recreate:
  1. Create a task (A) with event visibility set the "public" (standard setting in my case)
  2. Sync with Google Calendar (event appears in Google Calendar)
  3. Set event visibility of task (A) in Akiflow to "private" (see screenshot), don't change anything else
  4. Sync with Google Calendar (add other tasks or so to see that syncing happened)
  5. Problem: Visibility of task (A) remains "public" -> it doesn't sync with Google Calendar until another attribute (duration, time, title) is also changed.