fusion-mpt SAS problems on 12.1-RELEASE

This is my SAS HBA, I've got SATA drives connected to it, and have been running it since 11.1.

mps0@pci0:2:0:0: class=0x010700 card=0x040015d9 chip=0x00721000 rev=0x03 hdr=0x00
vendor = 'Broadcom / LSI'
device = 'SAS2008 PCI-Express Fusion-MPT SAS-2 [Falcon]'
class = mass storage
subclass = SAS

I had catastrophic drive failure problems when I was on 12.1-U1. Going back to 12.0, everything is fine and stable.

I had constant this in dmesg:

mps0: IOC Fault 0x40000d04, Resetting
mps0: Reinitializing controller
mps0: Firmware: 20.00.04.00, Driver: 21.02.00.00-fbsd
mps0: IOCCapabilities: 1285c<ScsiTaskFull,DiagTrace,SnapBuf,EEDP,TransRetry,EventReplay,HostDisc>
(da9:mps0:0:17:0): Invalidating pack
da9 at mps0 bus 0 scbus0 target 17 lun 0
da9: <ATA WDC WD2001FFSX-6 0A81> s/n WD-WMC5C0D6YZ1L detached
mps0: Error reading device 0xd SATA PASSTHRU; iocstatus= 0x47
mps0: Error reading device 0xd SATA PASSTHRU; iocstatus= 0x804b
mps0: Sleeping 3 seconds after SATA ID error to wait for spinup

It would bounce across disks, it didn't matter what was actually going on. The system died hard, and reboots and other things would not fix it. I had to go back to 12.0-RELEASE.

If I boot up 12.1, everything starts freaking out, and i have data corruption problems, because drives get randomly removed, detached and attached. It was rather chaotic to try and figure out.