For anyone that is having this issue I figured out how to get it to work. You need to use the block definition component, expode gets you geometry but without the GUID. Get the GUID of the object and then replace that with the one in the field. Somehow the GUID of the field used to create the field pre-block creation gets redefined post-block creation. Potentiall same issue as discussed here:
Since I’m doing this in grasshopper, I can just find the length etc and write this to a key value pair. I think this is a better work flow if you are not having users update the block manually.