You could try the Create receive mode if you’re using the legacy AutoCAD connector, I believe the default Update mode only updates the position of new blocks, but won’t update the definition of the block itself, if the block already exists in your document. The Create mode will always create new blocks with new definitions, but the downside is that it wont delete the old blocks.
A more exciting update: the new Grasshopper 3.5.0 beta connector now includes blocks and nested blocks, you can install it from the app and test it out! See this post for all updates:🚀 Grasshopper Beta is Here
When receiving these blocks in our new Autocad connector, your previous layers and blocks will be deleted and replaced with the new layers and blocks.