Hey everyone,
I rarely work with joomla, but ran into this issue.

The issue also seems to affect the filter functionality (but I had no time to properly test this) and might be related to issues #38355, #40068 and #40069.

At least for the wrong API return the cause seems quite clear (see below).

Steps to reproduce the issue

Request any article via the webservice/API that has tags assigned to it.
The ids and names of the tags are/might be mismatched (could have been caused by re-sorting/changes to the tags hierarchy/nesting).

This is the basic tag structure:

And an article with tags "M" (ID 2), "T" (ID 3) and "D" (ID 26) assigned to it.

Expected result

Result having matching IDs/names

...
state: 1,
tags: {
   2: "M...",
   3: "T...",
  26: "D..."
}
...

Actual result

IDs/name do not match

System information (as much as possible)

Joomla! Version: 4.3.3
PHP Version: 8.1.21

Additional comments

The cause for the mismatched API return can be found here:
api/components/com_content/src/View/Articles/JsonapiView.php

In both cases highlighted $tagsIds and $tagsNames do not (necessarily) match (automatically) and should be properly checked/associated with each other or their right order has to be guaranteed.

Perhaps it would be better to either fetch the tag data including the names based on the item ID (see TagsHelper::getTagIds) or to change the underlying queries, so that both the tags within the items object and the return from getTagIds have a guaranteed (and stable) order.
At first glance, getTagIds does not seem to have any order specified in the query - which means, it is not guaranteed.

Again, unfortunately I really know very little about joomla's structure and the effect changes might have, so unfortunately I cannot provide a fix.