Editor Sticks at 75% when using Constructor Helpers but only with certain info in Data Table

I have a data table which, among other things, contains a TSubclassOf AActor. In the constructor of my base actor class, I use a constructor helper to get the data table. When the TSO AActor is set to none, the editor loads normally but when I set this to an actor, the editor gets stuck loading at 75% and, it seems to reference the data table. When I comment out the constructor helper, it loads normally again.

Given what I have planned, there will be loads of items in my game so I was hoping to use the helper to make sure I didn’t miss any items out with the data table but this problem will prevent this.

Does anyone have any thoughts on how I can sort this out?