Unexpected re-evaluation (loop) by line break in RHS

when
    $fact : MathFact( bigDecimal1 != null, bigDecimal2 != null );
then
    // Notice the calculation is split over lines and this time starts on the line after assignment.
    BigDecimal result =
        $fact.getBigDecimal1().subtract($fact.getBigDecimal2());
       
    System.out.println("\nMathFact.result: " + result);
 
    modify($fact) {
        setBigDecimalResult(result);
    };
end