Hello Satoshi,
Thanks for using our community. These are the answers to your questions:
[A1] You meant “Buck regulators”, not “back”. Actually, the MMPF0100 has four buck regulators with up to six outputs; they can operate in PFM, APS and PWM switching modes. Therefore, switching regulators rely on the buck regulators; hence the switching regulators would be affected by ER19 too. The glitch is only for the buck regulators, not for VGENx, VGENx regulator might not start only. Please take a look at the MMPF0100 internal block diagram in page 6 of the following document:
http://cache.freescale.com/files/analog/doc/data_sheet/MMPF0100.pdf
[A2] ER19 refers to a startup condition; after the MMPF0100 has been successfully started, ER19 would not be valid. So, you’re correct.
Hope you find them useful, please let me know if I can help any further.
Josh