This bug is very similar to JDK-8195675. The user reports that the input field ignores certain characters when using a custom input source with an RTL keyboard. It appears that all versions of JavaFX are affected. Below are the instructions to reproduce the issue

1. Download and install Keyman at https://keyman.com/mac/.
2. Get and install the Hebrew (SIL) Keyman keyboard at https://keyman.com/keyboards/sil_hebrew
3. Get and compile the test app https://github.com/AndyBlack/KeymanFX
4. Change the keyboard to use Keyman (and select the Hebrew (SIL) keyboard).
5. Run the test app
6. Type "bdg" in the text box.
7. Expected is the Hebrew ( בדג ) but JavaFX one shows "bdg"

Instruction to compile and run the app
1. $JAVA_HOME/bin/javac src/application/MainFX.java
2. $JAVA_HOME/bin/java -cp src/application/ MainFX

For comparison, the Swing test application (https://github.com/AndyBlack/KeymanSwing) prints the expected string.

As I side effect I see error message at the console upon app start
2025-05-09 19:59:54.027 java[68181:56520069] error messaging the mach port for IMKCFRunLoopWakeUpReliable