applying more pressure to the heel when you step in is pretty normal (well for me anyway)
Also, was there snow/ice inder the heel of your boot? That often happens to me and the dildo won't engage properly
As for coming out and the heel staying down? that could indicate that either the forward pressure isn't set right, the torque range/forward lean isn't right, or simply you care releasing out of the toe and the din on the toe should be increased.
Maybe take it into the shop that mounted them and get them to have a look?