I was under the impression that when I had my tiu's updated I would lose my record/playback sessions. I don't think that is the case.
Whoever told you that, was mistaken. Your TIUs will not lose their Record/Playback sessions unless they are Factory (not Feature) Reset.
When I started to record a new session using my iPhone, I had some funky stuff happen and that led me to suspect the existing sessions.
What kind of "funky stuff" did you experience?
The only Record/Playback issue of which I'm aware is that of a bug in the app that only appears in Super TIU mode. The app only records switch track and accessory operation from the TIU that's selected when recording the session. When recording under Super TIU mode using the remote, even though it's required to select a TIU, the session uses all TIUs and is recorded in all TIUs.
This is on the list to be corrected in a future release of the app.