setup: being in the 3 panel view with the see also/classify sidebar visible. 1 document selected, editing it in the preview panel.
changing this document via the preview panel and saving it does not update ‘see also’/classify in the sidebar. to see an update requires leaving the record and re-selecting it
I can see why keeping the “see also” panel’s display static would be useful for researchers – personally, I prefer it that way so I have time to think about the suggestions shown in that panel. If the display were changing every time I typed a word in a document – extreme case, I know, but bear with me – I think the vertigo would make the panel not useful. 
Bugs are things not working as designed (or advertised). I don’t thing “see also” is advertised as being dynamic while the focus is on a given record. That sounds like a feature request.
(IIRC, a long time past there was a suggestion that “see also” have a text field and operate in a mode like Search.)
i agree.
no update while typing is not the bug. the bug is imo when you save the document and it wont update. at this point the state of the document has changed. thats why you get a different list of items in the see also/classify list when you switch to another item and back.
if the state of something changes and the change is persistent, it should be reflected.
additionally: same thing happens when you select a record, leave it unchanged, open a second window, change a properties of a group (e.g. exclude from classification)… the sidebar of window 1 will not update.