"{configuration=1}" seems to get broken after a "load append".
Exemple ;
$ load =2pie
LIGASE 13-APR-07 2PIE
CRYSTAL STRUCTURE OF THE FHA DOMAIN OF RNF8 IN COMPLEX WITH IT
OPTIMAL PHOSPHOPEPTIDE
found biomolecule 1: A, F
2PIE
$ print {file=1}.size
1429
$ print {file=1 and configuration=1}.size
1313
$ load append =2fez
2 models
$ print {file=1}.size
1429
$ print {file=1 and configuration=1}.size
1429