Google was pretty late in introducing offline messaging to Gtalk. IMO, offline messaging is one of the most used feature and it was good to see Gtalk finally allowing offline messaging.
However, off late, I noticed that I was not getting offline messages delivered to my Gtalk client for one of my Google account. I tried with my another account and the feature worked perfectly. This made me investigate as to what were the differences between the two accounts.
It struck me that the account to which offline messages were delivered only as emails and not as actual messages on Gtalk client, had a filter which made all the messages addressed directly to me skip the Inbox and go directly to a particular label - I do this with most of my email accounts.
Now Gtalk client, apparently, can only retrieve offline messages if they are labeled as "Chats" and "Inbox". And in my case they were labeled as "Chats" and "MyOwnLabel".
If you don't like offline messages for some weird reasons, try following steps with your Google account:
1. Create a Filter which is applied to all the messages that have your own email address in the "To" field.
2. Make sure you select "Skip Inbox" and apply your own label - say "MyMails" - while creating this filter.
3. Save this filter and now when anyone sends an offline message to your Google account, you will only see it as an email in your "MyMails" label and not as a message window on your Gtalk client.
What say? A bug? Or a Feature?