Full Text Index STOP POPULATION doesn't work, depending on Track Changes setting

Question

I had a Full Text Index population going on for too much time and storage, so I decided to stop it, but the population didn't stop.

Notes:

• Both index and catalog are created using the Full Text Indexing Wizard (right-click on table name > Full Text Index > Define Full-Text Index).
• I reproduced the problem several times (and still can), and the following describes what I experienced with the different Track Changes options: automatic, manual, and no tracking.
• Dropping the index and the catalog works without no problem.

Track Changes: Automatically

1. I first tried to stop it using:

   Right-click on table > Full-Text Index > Stop Population
   

   Which popped up a success window, while actually the population continued (confirmed by executing one of the queries posted here, and exec sp_spaceused MyTable which constantly showed a growing storage usage).

2. I then tried executing:

   ALTER FULLTEXT INDEX ON MyTable STOP POPULATION
   

   Which failed with the following error:

   Warning: Full-text auto propagation is on. Stop crawl request is ignored.
   

   Although it's only a "warning", the command was in fact ignored, and the population continued.

3. I then tried another option:

   EXEC sp_fulltext_catalog 'MyFullTextCatalog', 'stop'
   

   Which resulted in the same warning.

Track Changes: Manually

I followed the exact three steps above, but the results were somewhat different:

1. For step 1, I again got a success window, while population still continued.

2. For step 2, I got an error:

   Invalid object name 'MyFullTextCatalog'.
   

3. For step 3, I got a warning:

   Warning: The ongoing population is necessary to ensure an up-to-date index. If needed, stop change tracking first, and then deactivate the full-text index population.
   

Track Changes: None (success!)

I followed the exact three steps above, but now experienced success:

1. For step 1, I got a success window, and the population actually stopped.

2. For step 2 (after I recreated the index using the wizard), I got the same error as above:

   Invalid object name 'MyFullTextCatalog'.
   

3. For step 3 (after I recreated the index using the wizard), I got a success message, and the population did stop.

Question
What's causing the warnings\errors which prevent population from stopping (well, at least for auto and manual tracking)?