Calendar drops people off invite list

Every time I (Scoutmaster) create a calendar event in Scoutbook plus, I invite all parents, scouts, and leaders to the event. And every time, there are a subset of people who fall off the invited list and need to be added to the event in order to be accounted for when taking attendance. It is always the same scouts and leaders (including, ironically, both my committee chair and me) every time. This happens whether it is a one-time event or if I choose to create a recurring event series.

@ChristopherCutler have you tested if the same happens if another users makes it?

I think I am seeing similar but only for youths. I updated all our events and will watch closely if I see it drop again.

For the developers: I am adding using the 3 invite all buttons for youth, parents, and leaders and checking all 3 add future checkboxes.

Do this for us
with you logged in
Give us Date/Title of Event
Then list the Member # (no name) of at least some of those that have dropped.
So we have a clear example