After 6 years of pain I was able to find steps to get this bug happen.
Please take a look at the GIF and try these steps:
1. Open a new doc
2. Create a rectangle
3. Use Object > Artboards > Convert to Artboards
4. Undo — notice there is no rectangle left, even though it makes sense to have it back. Ai shows the step for it though!
Create another rectangle and convert it to artboard again (I use a hotkey now) — notice how the name is now 'Artboard 4' (not 'Artboard 2', how it should be — http://illustrator.uservoice.com/forums/333657/suggestions/36673057, — and not even 'Artboard 3', but 4!)
5. Undo again
6. Now create a third rectangle and convert it, and then the fourth rectangle and convert it too — notice the numbers are 1, 2, 4 (!!!), and the names are 1, 5, 5!

I. Hate. This. Bug.
It costed me a month salary once.
Made the team aware.

I'm on a Mac/OS, and I wanted to export my work and I see that after the 10th artboard, it's somehow... 12? (Where is 11?)

I tried to delete the 10th and "12th" artboard, and then added new artboards, but it's still 10, and then 12.

The problem has reappeared, please fix it as soon as possible. This issue can lead to loss of artwork when exporting, especially when there are many drawing boards, which are not easily detected.

When can this bug be fixed? This problem has existed for many years. It occurs irregularly and can be restored by restarting the software.

Folks, this has been happening for YEARS. The earliest report of this bug that I can find is from 2017, and Adobe has yet to fix it.

I have a file with multiple artboards (155 to be exact).
Noticed that Illustrator is not numbering them correctly around the number 80, repeating some numbers. It's also not exporting all of them. In 155 files, 3 were not exported!

The numbering of the artboards show "16" instead of "15".

MacOS 14.4.1 / Illustrator 28.4.1
When I duplicate the artboard by command + drag, I found that the artboard number got wrong. It appeared two "38" and two "40". Although it can be fixed by restarting, but I expect a bug should not occur in such simple action. Thanks!

Just had the bug happen to me again on Windows. I've provided a memory dump as requested by Egor.

The number of the drawing board is repeated

I created 15 distinct artboards...but it created artboard 14 twice...so when I exported all the artboards it skipped the one that should have been artboard 13

Non esiste la tavola da disegno n°4

Non esiste la tavola da disegno n°4

Still present on the latest update in mid November 2023.

Two artboards are numbered as artboard 12. This is not the artboard name- those can be changed and different - but the number that refers to the order. I can delete the second artboard 12, but then, what was 13 is another artboard 12. This is very inconvenient for saving and printing as it won't save or print both artboard 12s, just one of them.

Artboard number duplication bug

When creating artboards, after reaching artboard num. 49 the next artboard and the one after that will both be number 51, skipping 50. When exporting all artboards as images, only one of the arboards labelled '51' will get exported.

This happens on both the latest Windows and MacOS versions of Illustrator.

When I created a new artboard (either by clicking the button or duplicating) after Artboard #39, #40 is always skipped.

The artboard numbering is broken. Screenshot shows how artboard numbers go 5, 6, 8, 8, 10, 10, 11, 12, 14, 14, 15 etc.

アートボードの6枚目を作成すると、「6」ではなく「7」が作成されてしまいます。（添付した画像を参照）
自分で修正することは可能ですか？