I would like to request you to check the SPICE model of UCC5350SBD.
The model of UCC5350MCD has been modified to avoid "False turn ON of upper NMOS.".
On the other hand, the model of UCC5350SBD has not been modified.
Does the same problem not occur in UCC5350SBD?
UCC5350MCD(Rev. A): www.ti.com/.../sllm368