Inconsistent updating of gCal from Appointments+

It appears that edits made to appointments and saved do not get pushed through to the gCal consistently.
Example is on the fairmont site of my multisite installation on lgfws.com - I have a custom field: FIELD_ORGANIZATION and the NOTES field both appearing in the description that is displayed in the gCal. When these fields are updated in Appointments, I would expect those changes to flow through to gCal but it is inconsistent. The first change I made to FIELD_ORGANIZATION went though, but when i changed them again, it won't update. (I am adding the characters "CN" so that it is easy for volunteers to know which trips have a Crew Needed - then when the volunteers have indicated their interest, I am removing those characters)

I have waited over an hour to see if the changes propagate but they don't.

Is there something I'm missing? A setting I should make?