2.6.2 : FZ syntax error, unexpected '(' expecting FZ_ID

[Madoxen]

I've been redirected to issues from here
I'm getting a cryptic error during compilation to FlatZinc:

Error: Unknown character in line no. 1914
Error: Unknown character in line no. 1914
Error: Unknown character in line no. 1914
Error: syntax error, unexpected '(', expecting FZ_ID in line no. 1914

Below I've attached the FlatZinc output (with line numbers in square brackets):

[1913] constraint int_lin_eq([1,1,1,-1],[X_INTRODUCED_894_,X_INTRODUCED_908_,X_INTRODUCED_922_,X_INTRODUCED_955_],0):: defines_var(X_INTRODUCED_955_);
[1914] constraint '-'(X_INTRODUCED_954_,X_INTRODUCED_952_,X_INTRODUCED_956_):: defines_var(X_INTRODUCED_956_);
[1915] constraint '-'(X_INTRODUCED_956_,X_INTRODUCED_955_,X_INTRODUCED_957_):: defines_var(X_INTRODUCED_957_);
[1916] constraint int_ne_reif(X_INTRODUCED_963_,0,X_INTRODUCED_962_):: defines_var(X_INTRODUCED_962_);

It seems like minizinc is generating invalid FZ code.

I've attached my full model with FZ output below:
enroll.mzn.txt
enroll.fzn.txt

[Dekker1]

What command are you using to compile the FlatZinc file? It is important to know what MiniZinc library (for what solver) is being used.

[Madoxen]

@Dekker1 The command is as follows:
minizinc -i -c enroll.mzn data/trivial.dzn -p 12 Remove -c to see the error. I'm using Gecode 6.2.0 as a solver.

I'm attaching data file below, so that you can evaluate it:
trivial copy.dzn.txt

[Dekker1]

It seemed that there was an internal mismatch between the version of the operator that was matched at type checking and the version that was actually used during flattening because the types of the arguments was different after they were flattened. Because of this problem the name of the operator wasn't correctly converted to it's FlatZinc equivalent.

The issue should be resolved in the next release