that's a benefit of zfs, it doesn't trust the drives actually wrote the data to the drives, the so called RAID write hole, since most RAID doesn't actually do that checking and drives don't have the per block checksums in a long time. It checksums to ensure.
The issue with flaky bridge chips wasn't usually about data integrity——it works fine most of the time, i.e. data written got read back correctly.
But often after extensive use, `dmesg` would complain about problems when talking to the drives, e.g. drive not responding or other strange error messages (forgot the exact text but very irritating and google-fu didn't help). There were also problems with SMART commands passthrough and drive power management e.g. sleep/standby adjustment which wasn't reliable when talking via bridge chips.
I use only disks directly connected to SATA controllers afterwards and no such issues ever happened again.
