Calendar BU not keeping colors?

It’s probably something I’m not doing correctly but I can’t figure out why.

If I create a calendar Archive on my main iMac by selecting File/Export Calendar Archive. Move the resulting archive file to my Mac Air, use File Import to restore from that archive and selecting to overwrite everything on my MacAir all the calendars have lost their specific colors. They all come out showing as red which is the first non-custom color.

Is there any way to force the calendar to use the colors I selected in the master that I am making the archive from?

FWIW, I’ve found when you export a calendar’s information from iCalendar it does contain the color data.

Screen Shot 2022-01-28 at 10.48.17 AM

But when you import the .ics file it assumes the color of the target calendar. Would it be possible to create a new calendar and set the color before import?

It’s not a .ics file it’s a .icbu file and it includes all 15 of my calendars in it. I’m not targeting any particulr calendar I’m say do a total replace on anything on the lptop as in All the existing data can be ignored.

Does it restore 15 separate calendars? Or does it put everything into 1 upon import?

15 separate calendars so it shoul;d be pulling data from the color if it’s in the Archive

.icbu files appear to have color data in an Info.plist in the directory containing data about each calendar.

It might be possible to edit this file for each calendar but, IMO, it would be a matter of trial and error. I can’t find any data on how an icbu file is constructed.