core-shell problem with equilibration

Dear All,
I've got a strange behavior for a core-shell model.
We are modelling an oxide with a core -shell interaction according to the recent literature. The interaction is based on a Buckingham two body potential.
First of all I want to specify that if I model the system without a the core-shell everything seems working well, equilibration proceeds correctly and the program ends correctly.
However, and very strange to me, if I employ the core-shell model the program ends correctly only without equilibration in nve/nvt/npt. With equilibration, on the contrary, it starts with a wrong total energy (the two body energy comes out to be unphysically small in this case) during the equilibration period while it suddenly recover the correct energy value at the equilibration end but then the program immediately crashes with 474 error and with the energy largely deviating from the correct value.
I went through the program source routines and I did not find any clear source of this ill-behaved end.
I'm using mpi compiled dl-poly 4.10 version.
I wander if anyone has already experienced this behavior.
Any help is appreciated
thank you

Hi Giuseppe,

can you email the inputs to [email protected]