This is an old thread about a previous version of Ubuntu Touch.
I guess it has something to do with how the installation is done.
I don't have this device, but my advice is to read the other threads in this category where people have trouble installing UT. You'll find useful information on how to prepare your device for installation.
Sometimes some device require specific steps such as deleting the existing partitions in TWRP or installing Android back and then trying again, ...
Best of luck.