Heya.
I just faced this issue as well, with my spawned-in mesh from the BP not being present.
My fix for this scenario was pulling ff the ‘Add Spline Mesh Component’ node that I was using from the ‘Return Value’ variable output, plugging into a node called ‘Set Collision Enabled’, with the ‘New Type’ being ‘Collision Enabled (Query and Physics)’.
Image attached for reference.
I hope this helps someone else out 
