From what I've been able to piece apart from all the talk about this, I think the test should be as this...
User A should start to compose a SMS to User B. User C composes and sends a SMS to User A, and it is received by User A before he sends his composed message to User B. User A then sends his message, and see who receives it even though it was intended for User B. (it's a lot simpler than it reads lol)
My theory is that an SMS that is being composed is having it's recipient changed when an incoming SMS interrupts it.
After picking apart all the reports on various sites, that's how I see it happening. Personally, I think it's an issue of having more than one sms messenger on your device, or a SMS widget, and they're conflicting with each other.
Anybody able to replicate the bug should list the following items...
- Which SMS client it affects
- List all SMS clients installed on the device
- List any/all widgets installed that are even remotely related to SMS
- Device used
- OS version
- UI (sense, motoblur etc)
- Any activity on the device within the previous 20 minutes (a bit long, but hey, who knows)
The key is finding a common denominator.
[edit] Another thought just occurred to me. Verify whether there are any unsent Drafts (text messages composed, but not sent for whatever reason).