Strange result Jsprit

Hello, when we have 2 vehicles, exactly the same and use the settings below always vehicle A gets the Job, we have implemented our own skill score usind the CostCalculator. When we give user B better skills (higher score), we see that B is never calculated, when we remove vehicle A, then B is calculated correctly and the score is lower then when A does the job because of the bonus we give based on the skill score. The strange thing is that when A and B our both in the problem B is not calculated but when we do vraBuilder.setNuOfThreads(2); everything is just fine and we see both vehicles calculated and B wins.

xmlConfig.setProperty(“iterations”, apmBatch.IsAdvisor ? apmSettings.IterationAdvisor.ToString() : apmSettings.Iteration.ToString());
xmlConfig.setProperty(“construction.insertion[@name]”, “bestInsertion”);

        xmlConfig.setProperty("strategy.memory", 5);
        var searchStrategy = "strategy.searchStrategies.searchStrategy";

        xmlConfig.setProperty(searchStrategy + "(0)[@name]", "random_best");
        xmlConfig.setProperty(searchStrategy + "(0).selector[@name]", "selectBest");
        xmlConfig.setProperty(searchStrategy + "(0).acceptor[@name]", "acceptNewRemoveWorst");
        xmlConfig.setProperty(searchStrategy + "(0).modules.module(0)[@name]", "ruin_and_recreate");
        xmlConfig.setProperty(searchStrategy + "(0).modules.module(0).ruin[@name]", "randomRuin");
        xmlConfig.setProperty(searchStrategy + "(0).modules.module(0).ruin.share", "0.3");
        xmlConfig.setProperty(searchStrategy + "(0).modules.module(0).insertion[@name]", "bestInsertion");
        xmlConfig.setProperty(searchStrategy + "(0).probability", "0.5");

        xmlConfig.setProperty(searchStrategy + "(1)[@name]", "radial_best");
        xmlConfig.setProperty(searchStrategy + "(1).selector[@name]", "selectBest");
        xmlConfig.setProperty(searchStrategy + "(1).acceptor[@name]", "acceptNewRemoveWorst");
        xmlConfig.setProperty(searchStrategy + "(1).modules.module(0)[@name]", "ruin_and_recreate");
        xmlConfig.setProperty(searchStrategy + "(1).modules.module(0).ruin[@name]", "radialRuin");
        xmlConfig.setProperty(searchStrategy + "(1).modules.module(0).ruin.share", "0.15");
        xmlConfig.setProperty(searchStrategy + "(1).modules.module(0).insertion[@name]", "bestInsertion");
        xmlConfig.setProperty(searchStrategy + "(1).probability", "0.5");

Any news on this post ?