From my testing it appears that the SPI modules's STAT:MSTIDLE flag does not assert (change to 1) until the slave select gets deasserted. The user manual does not indicate MSTIDLE has any interaction with the slave select pin logic. This is what the user manual says:
I originally asked a similar question about a year ago that was buried with many more details here: Explain the SPI peripheral's MSTIDLE flag for LPC84x. I wanted to ask this question again in a much simpler way.
So can this behavior be confirmed as correct? Does the user guide documentation need to be updated? Should this be an errata? Does someone want to challenge my findings? Etc?