The stock messaging app on my phone running Android 4.2.1 seems to occasionally create new threads for text messages from those senders with names but no numbers (companies such as O2).
When I get texts from O2 sometimes my phone makes a new thread, despite having the older messages. It should really add to the previous conversation. It's making my inbox messy with several conversations from the same person/company, I also don't want to delete any messages for future references.