Hi twinkerzzz
What should happen is UC should sent out a stop notice to various departments such as ESA, JSA, HB ...
Sometimes when there is a hold up in proving your identity, the stop notice is delayed being sent out and legacy payments will continue as normal which then creates an overpayment.
If you receive payment from UC and IR ESA then contact IR ESA and inform them you are in receipt of UC.
Gary
Nothing on this board constitutes legal advice - always consult a professional about specific problems