I faced similar problem.
It was solved by flashing via fastboot stock nonGPE ROM prior to CM.
To be exact, i've got xt1032 GPE 16Gb and used ROM named XT1032_FALCON_RETEU_5.1_LPB23.13-56_cid7_CFC.xml.zip.
Unbelievable it's working!!!
thank you very much.
i found your rom here:
https://www.androidfilehost.com/?fid=24052804347848287
after downloading i extract the ZIP.
then i flashed via mfastboot.
i'm using linux to flash so this is how all the proccess looked like:
PHP:
sudo mfastboot flash partition gpt.bin
sudo mfastboot flash motoboot motoboot.img
sudo mfastboot flash logo logo.bin
sudo mfastboot flash boot boot.img
sudo mfastboot flash recovery recovery.img
sudo mfastboot flash system system.img_sparsechunk.0
sudo mfastboot flash system system.img_sparsechunk.1
sudo mfastboot flash system system.img_sparsechunk.2
sudo mfastboot flash system system.img_sparsechunk.3
sudo mfastboot flash modem NON-HLOS.bin
sudo mfastboot erase modemst1
sudo mfastboot erase modemst2
sudo mfastboot flash fsg fsg.mbn
sudo mfastboot erase cache
sudo mfastboot erase userdata
sudo mfastboot reboot
(in windows there is no need for "sudo")
i did it line by line(but you can do a batch file. i don't know how)
all worked great besides erasing the userdata that didn't succeed.
i ignored it and continue.
i open the phone and the phone started with the newly android 5.1.
after it finished starting, i powered off the device and get into fastboot mode.
then i flashed the latest TWRP recovery from here:
http://forum.xda-developers.com/moto-g/development/recovery-twrp-2-8-2-0-touch-recovery-t2980621
and after that i move the latest(to this date) cm 13 rom into the device.
from TWRP recovery i flashed the CM rom and it was a successful flash!!!

.
after that i download slim mini gapps from here:
https://www.androidfilehost.com/?w=files&flid=48213
move it to sdcard and from TWRP i flashed it.
when i boot up again there was a problem with the downloaded gapps from before(it gave me a message the never stoped appearing).
so i again go into twrp and from there i did a factory reset, open the phone and now i have a working cm with gapps without a problem
p.s.
the only "bad" thing is the annoying "warning Bootloader unlocked" message that suddenly appeared(after the installation of android 5.1).
you can see it here:
https://i.ytimg.com/vi/Shn8wk4nGGU/maxresdefault.jpg
to solve this i downloaded from here:
http://forum.xda-developers.com/showthread.php?t=2710817
new logo(it comes in ZIP file that needs to be extracted), and flashed it (when i inside fastboot mode), with this command:
sudo fastboot flash logo PATH-TO-logo.bin (i.e. you need to specify the exact path to logo.bin)
in my linux computer, logo.bin was on desktop so what i really wrote is this:
sudo fastboot flash logo Desktop/logo.bin
after finished and starting the device i saw the new logo and the warning message disappear.