ADDITIONAL SYSTEM INFORMATION :
java.vm.vendor=Oracle Corporation
java.vm.name=Java HotSpot(TM) 64-Bit Server VM
java.version=1.8.0_221
java.specification.version=1.8
java.runtime.version=1.8.0_221-b11
user.language=en
user.country=GB
user.variant=
Default locale=en_GB
os.name=Mac OS X
os.arch=x86_64
os.version=10.16

A DESCRIPTION OF THE PROBLEM :
As a result of https://bugs.openjdk.java.net/browse/JDK-8025636 lambdas are hidden in stack traces.
Sadly, that is true only when stack trace is taken from the same thread.
When Thread.getStackTrace() is taken from a different thread than the invoked object, the stack trace still contains lambdas.

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
Run the attached application.

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
----------From different thread----------
java.lang.Thread.sleep(Native Method)
HiddenLambda.bar(HiddenLambda.java:36)
HiddenLambda.lambda$null$0(HiddenLambda.java:10)
HiddenLambda.foo(HiddenLambda.java:31)
HiddenLambda.lambda$main$1(HiddenLambda.java:10)
java.lang.Thread.run(Thread.java:748)
----------From the same thread----------
HiddenLambda.bar(HiddenLambda.java:38)
HiddenLambda.lambda$null$0(HiddenLambda.java:10)
HiddenLambda.foo(HiddenLambda.java:31)
HiddenLambda.lambda$main$1(HiddenLambda.java:10)
java.lang.Thread.run(Thread.java:748)
ACTUAL -
----------From different thread----------
java.lang.Thread.sleep(Native Method)
HiddenLambda.bar(HiddenLambda.java:36)
HiddenLambda.lambda$null$0(HiddenLambda.java:10)
HiddenLambda$$Lambda$2/277640063.run(Unknown Source)
HiddenLambda.foo(HiddenLambda.java:31)
HiddenLambda.lambda$main$1(HiddenLambda.java:10)
HiddenLambda$$Lambda$1/531885035.run(Unknown Source)
java.lang.Thread.run(Thread.java:748)
----------From the same thread----------
HiddenLambda.bar(HiddenLambda.java:38)
HiddenLambda.lambda$null$0(HiddenLambda.java:10)
HiddenLambda.foo(HiddenLambda.java:31)
HiddenLambda.lambda$main$1(HiddenLambda.java:10)
java.lang.Thread.run(Thread.java:748)

---------- BEGIN SOURCE ----------
import java.util.Arrays;
import java.util.List;
import java.util.Set;

public class HiddenLambda {

    public static void main(String[] args) {
        Thread myThread = new Thread(()->
        {
            foo(() -> bar());
        });
        myThread.start();
        Set<Thread> threads = Thread.getAllStackTraces().keySet();
        for (Thread thread : threads) {
            if (myThread == thread){
                System.out.println("----------From a different thread----------");
                List<StackTraceElement> stackTraceElements = Arrays.asList(thread.getStackTrace());
                for (StackTraceElement stackTraceElement : stackTraceElements) {
                    System.out.println(stackTraceElement);
                }
            }
        }
        try {
            myThread.join();
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
    }

    static void foo(Runnable lambda) {
        lambda.run();
    }

    static void bar() {
        try {
            Thread.sleep(1000);
            System.out.println("----------From the same thread----------");
            List<StackTraceElement> stackTraceElements = Arrays.asList((new Exception()).getStackTrace());
            for (StackTraceElement stackTraceElement : stackTraceElements) {
                System.out.println(stackTraceElement);
            }
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
    }
}
---------- END SOURCE ----------

CUSTOMER SUBMITTED WORKAROUND :
I found no workaround to hide the lambdas, but for consistency between snapshots you can disable hiding lambdas by adding VM options:
-XX:+UnlockDiagnosticVMOptions -XX:+ShowHiddenFrames

FREQUENCY : always