Trouble saving tune for HDT VK Commodore Group A

I’m trying to create and save a tune file for the HDT Commodore

Forza gives me the option to name and save a tune as normal, but then when I go to my tunes, the data is missing from the file I just created

All I get is warning triangles where the data should be and the PI is E100

I’ve tried getting and loading other tunes to overcome the bug but it hasn’t worked

Is there a limit to the number of tunes you can save ?

I’m on XBox 1