this is not in the fcom but I googled it.
This is due to the position and/or design of the RAT which supplies the DC ESS. On old models, the RAT stops working at 140kts (app speed when gear down). On new models, RAT are made to stall only at 100kts (after landing, when decelerating), so it does not relate to gear extension aynymore.
These are my two cent...