Doing x.stop_sequences() is causing this UVM FATAL Item_done() called with no outstanding requests. Each call to item_done() must be paired with a previous call to get_next_item()

In reply to uvm_va_1:

It is confusing what you are saying-- parent sequencer, top sequencer – and you run into this error after adding stop-sequences. You should not stop sequences because you’ll not know what the consequence is. Let your sequences running as you waant to have it.
Again, I do not understand your environment and I do not see how you are running your sequences. To see and understand this is necessary to give you an advice.