The 787 battery wake up call seems to have been treated as a one off without a deeper look into how that design snuck past the DERs.
IF i recall- at that time the DER " system" had been changed within Boeing as to who really had the last word and the DER as such had a new 3 or 4 letter designation.
With more a** covers needed.
And the 787 was neasrly immediately grounded despite no injuries.