You have a block images bug. Your /dev/ (or your gpt partition table, not sure) mmc partitions do not match with the sizes of partitions specified on BoardConfig.mk.
Or any other patch in CMs Gerrit that simply disables the use of "--block" arg...
Finally a temporary working method to use Systemless Xposed and bypass SafetyNet
Above works on Xiaomi.eu 6.9.29 (MIUI), marked temporary because if SafetyNet gets update again, it will probably fail again.
Use Suhide v0.55 and systemless ...
Version No : SOKP-L-5.1.1-LMY48I-R9.0
AOSP Version: Android L5.1.1 R9
Display advance Menu not working,
try to tap many time nothing happens....