There is 'graceful degradation', and this one is an ungraceful one. And then I’m asked but don’t I use Libraries. How can I use it it’s fragile AF?

But it also goes wrong the other way around: Pantone Solid Spot colors added from Illustrator to a CC Library lose their name and become Process colors in Illustrator. It just takes a couple of clicks (not predictable how many, but it always destroys the spot in the end) to transfer the spot to process. Then the library color is permanently changed. Illustrator does change the library color.

To add to what Egor said, spot color (actually every color added by Illustrator is not color managed, just a bunch of numbers) loses its Lab values. But Illustrator also destroys the colors in a CC Library. I rerecorded the steps and added a new one: once the color has become process magenta in the swatches, double clicking the color in the library changes it permanently to magenta. Switch back to InDesign shows a Process Magenta Pantone Blue...

When I try to replicate this, following the steps from the video, I notice this:
1. If I create a shape first and then apply the spot color from a Library directly to it, it gets added as 'blue', but not in Lab, but in RGB! Why not Lab? I check 'Spot Colors' dialog in the Swatches panel’s menu (not many know about this one, BTW), and clearly says 'Use Lab values).
2. If I don’t have anything drawn on canvas and double-click the color in a Library — it gets added as a process magenta, just as reported by many.

This is not fixed after 7 years waiting. Create a Spot in InDesign, add it to a library. Add the color in a New InDesign doc by filling a rectangle, add the color by adding it to the swatches, works fine.
Go to Illustrator, create a new document, double click the spot and it becomes a magenta process color.

When I click on a color from my Library, it adds "Spot Color" to my swatch group, which is always Magenta. Each time I click, it adds another, and another, and another.

I'm not able to add any color or color theme to my swatches from a Library I've created. When I tap on "Add theme to swatches" or "add color to swatches" it adds a strong PINK color to swatches... just that... one swatch color.. the same one over and over and over.

If Global Colors are still not supported after 6 years, prevent them being added to a CC library.
There is no warning when the box is checked.

This bug makes using libraries very unintuitive!

See this example.

It is not only spot colors from InDesign that become magenta, Global colors from Illustrator have the same problem.

This problem needs to be fixed ASAP its annoying

This is STILL HAPPENING

When I add a color library, downloaded from Adobe to my library and I tried to import into swatches it changes to a magenta color. The folder also comes up, but has no colors added to it. It's been doing this for multiple versions for a while now.

I am using a PC and these are the specs:
Device name Laptop-RoseGold
Processor AMD Athlon Gold 3150U with Radeon Graphics 2.40 GHz
Installed RAM 8.00 GB (5.92 GB usable)
Device ID 8F7AE8FF-2B2A-40A1-A522-C798F101587D
Product ID 00325-82105-30687-AAOEM
System type 64-bit operating system, x64-based processor
Pen and touch Pen and touch support with 10 touch points

This is absolutely broken. It makes using creating your own themes useless.

It appears to only happen if the swatch added to cc libraries is global. It’s global is unchecked it seemingly works fine

How is this - what is obviously bug still not fixed!? Libraires *could* be one of Adobe's most useful features but it's so buggy and half-assed.

*STILL NOT FIXED* - Aug 2023

And similar reports here:
https://illustrator.uservoice.com/forums/601447-illustrator-desktop-bugs/suggestions/44787154-cc-library-to-illustrator-swatch-name-length-bug

https://community.adobe.com/t5/illustrator-discussions/erreur-du-nuancier-dans-la-bibliothèque/m-p/12794696#M312576

https://community.adobe.com/t5/illustrator-discussions/illustrator-libraries-edit-colours-adding-pink-swatch/m-p/12871650#M317972

It currently also happens with Global RGB colors added to the CC library. When added to another document from the CC library, they lose their name and become a magenta spot color.

Spot in Illustrator