When you say a STOP condition in middle of a data transfert, for a data transfert is only a byte transmission, or between bytes?
I don't expect a master generated a STOP condition between bits, but between bytes, and that should respect the protocol.
And in all case, when a STOP condition occurs at any time, the slave should be ready in the free time bus to received a START condition, beside that, added functionality to log this behavior is up to you to provide information to state-machine or the processor which is connected to this I2C slave.