Artboard numbers doubling up

2024, version 28.1 and I just noticed that since the last update I have this same problem but the numbers doubling up start at 14. It causes problems with exporting, Illustrator telling me that the range is incorrect. I need to have a few artboards empty put aside to use properly. Adobe, you think you can fix this??

Something might be corrupt in your prefs.Try the first 2 together wheil Ilustrato is quit, and if that foes nto work reisntall using lcearne.

PREFS  RESET MAC (thorough method)

Quit Illustrator

Finder >> Shift Command G

~/Library/Preferences/Adobe Illustrator 27 Settings/en_US/Adobe Illustrator Prefs

rename Adobe Illustrator 27 to Adobe Illustrator 27old

PREFS  RESET MAC (other)

Quit Illustrator

Finder >> Shift Command G

~/Library/Application Support/Adobe/Adobe Illustrator 27/

rename Adobe Illustrator 27  to Adobe Illustrator 27 old

Reinstall App

Use the Creative Cloud Cleaner to fully remove your app & prefs then reinstall

This issue has been appearing for years just for some people. It cannot be reproduced and that's why it's difficult to solve. 

I would assume that there is a report on uservoice that you can vote for. But again: the engineers will only be able to solve it when they can safely identify where it comes from. https://illustrator.uservoice.com 

I could not duplicate the problem using the latest version of Illustrator (27.7) with Monterey. Try deleting your Illustrator preference file. This will restore the program to its defaults which, hopefully, will fix the issue.

To do so on a Mac:

For Macintosh Users: The User Library folder in which Illustrator’s preferences are stored is hidden by default on most Macintoshes. To access it make sure that Illustrator is closed and click on the desktop to launch a Finder Window (Command-N).With this window in column view follow the path User>Home folder (it’s the folder with an icon that looks like a house—it may have the user’s name rather than “Home”) and click on the Home folder. With the Option Key pressed choose Library from the Finder Go Menu. “Library” will now appear within the Home folder. Within the Library folder find the folder called Preferences and within it find the folder called “Adobe Illustrator <Version #> Settings” (earlier versions of Illustrator might just say “Adobe Illustrator”) and the file called “com.adobe.Illustrator.plist” and delete both that folder and that file. When Illustrator is next launched it will create new preference files and the program will be restored to its defaults. 

The advantage of manually deleting preference files in this manner is that after you’ve reset up the program (make sure that no document window is open) to your liking, you can create copies of your personalized “mint” preference files (make sure that you quit the program before copying them—that finalizes your customization) and use them in the future to replace any corrupt versions you may need to delete.