Context.write method returns wrong result in Mapreduce java

Question

I'm new to hadoop, and I encountered a weird issue. here is the reducer code :

        @Override
        protected void reduce(Text key, Iterable<Deck> values, Context context) throws IOException, InterruptedException {
            Deck deck = processor.analyse(key.toString(),values);
            System.out.println(deck);
            context.write(key,deck);
        }

The weird issue here is that println displays right values of deck values, but I don't get the same result in the output file. here is the result :

... Wrong output (output file)
060C0E1F3133434B_2023   060C0E1F3133434B_2023,Nothing,0.0,Nothing,true,0,2,3,1,3990
... Right output (by debugging)
060C0E1F3133434B_2023   060C0E1F3133434B_2023,Nothing,0.0,Nothing,true,0,2,3,3,3990

Please could someone explain from where the issue came thanks.