L2-Memory, Error in on_chain_start callback: 'name'

When at cell In[4] I change the Verbose to True, in All following cells from the cell in[5] to cell in[7], I keep getting this warning:
Error in on_chain_start callback: ‘name’

what is the cause? how could it be solved?

it also happens in L3-chains, when in cell In[17] change the verbose=True.