inverse: z3_exception in mk_couple : Sort mismatch at argument #1 for function

This also seems to be the reason that test 1947 fails and had to be skipped, I get:

z3_exception in mk_couple : Sort mismatch at argument #1 for function (declare-fun couple (K (Array A Bool)) couple) supplied sort is L

PREDICATE is UNKNOWN: Sort mismatch at argument #1 for function (declare-fun couple (K (Array A Bool)) couple) supplied sort is L

### Evaluation error, expected result to be: TRUE (but was UNKNOWN) in :z3 x:liefert[{l1}] & k|->b : bes & x:b

With version 1.6.1 of ProB and 4.4.1 of Z3 it all still worked:

There seems to be a problem as soon as couples of different types are used, e.g. for

:z3 x ={1|->TRUE, 2|->FALSE} & y= {TRUE|->FALSE}