Further update - my colleague is now also experiencing the same after updating, so more likely a bug. Also, seems to be having other effects also – such as menus being 'greyed out', for example my 'Select Same' options are greyed out and also is I try the Type menu to 'Change Case' etc.

Is there a new update coming soon do we know?

Just discovered another quirk of this – I can't seem also to double click on swatches to open the properties window (for example if I'm renaming a spot or tweaking the colour values). This also applies to just renaming within the swatch window also.

Happens on new files as well as existing files.

I asked around, but at the moment I'm the only one on the most recent update. The video does show me 'trying' to click and hold/drag, and that's it not working.

However, talking with a colleague, for that issue we noticed it only seems to affect 'highlighted' colours. Un-highlighted ones will move, until they too are highlighted, and then they don't.

I'm still getting the multiple colours highlighted also, so think there is a bug somewhere.

The video doesn’t have the click and hold states recorded, but the gist is clear now, thanks.
Alas, I can’t replicate it with Pantone swatches in Large List view in 30.8.2 on Windows. It can be a Mac thing or something specific for your machine even, or the file (doubt it). If you have colleagues who has a similar setup — please ask them to test it. Will do the same. Thanks!

Thanks for the reply.

Made a recording of the swatch window. On this you can see the colours 'sticking' where I'm trying to reorder them. They move once, then get 'stuck', or don't move at all. Sometimes a second one highlights too even when not clicked. Seems to be happening with Spots?

The glitch where it doesn't always highlight or jump to the colour when selecting items on the artboard is a bit more random, so couldn't capture that.

I can't share the files due to client confidentiality unfortunately. I'll try and set up a generic file though.

Does this help?

Ben, no, this is the first time I hear of it.
Could you please record a video the next time you catch it? If possible, attach the file (if you are OK with sharing it publicly; if no — please email it instead to sharewithai@adobe.com, with the report’s link mentioned, https://illustrator.uservoice.com/forums/601447/suggestions/51812091)
Can you reproduce it in a new file? Does it happen with an swatch type or, perhaps, spot only? Please try to collect more info.