Adding to list of custom type it changes all values for a one of the sections

Hi All,
I have a custom type in my project containing a variety of things one of these is an array of Booleans, I then have a List of my custom type that a new ones gets added too when required. This is where the problem begins it adds the new item each time keeping most sections with the correct value however, the array of Booleans gets changed for every entry in the list each time rather than just the new entry, it only does this with the Boolean array all others are added as expected and don’t change upon adding a item any ideas what might be causing this? I print out the Boolean array for all skills after each new skills is added and first 7 Booleans linking to the Boolean array seem to all change to have the same value as the most recent skill, while all other values in the type remain as the values they were meant to be.