Whilst I know which cutscene you're referring to, could it be considered with complete certainty to be an exact replication of what may have happened? Or just a simple illustration to accompany Emet's story? As you know, Ryne herself wasn't affected in any way because it was only a demonstration. Hence, any after effects that may have applied had it been true wouldn't have been depicted. For example, if sundering had caused the individual to lose their memory or undergo an entire personality change, it wouldn't have been shown; True Ryne would still maintain her own personality because she wasn't sundered. The second Ryne would only depict identical looks, not any hidden effects. We would have to rely on Emet's description and, whilst he listed one or two effects, he couldn't realistically list everything.
I wish we knew more...