Your workspace contains mod elements that don't compile correctly

So, I exported a JAVA model from Blockbench (I picked Forge 1.7 - 1.13 for the model), and then I put on MC, but when I tried to run the mod this appeared "Your workspace contains mod elements that don't compile correctly".

But I don't know what I'm doing wrong, the JAVA model that I exported don't has a superior version to 1.15 and I'm using Mcreator 2021.1, I also tried export with "Forge 1.14 (MCP)" and "Forge 1.14 (Mojamps)" but both also ended on this way.

The console from the error:

Executing Gradle task: runClient
Build info: MCreator 2021.1.18117, forge-1.16.5, 64-bit, 12173 MB, Windows 10, JVM 1.8.0_275, JAVA_HOME: C:\Program Files\Pylo\MCreator\jdk
> Task :compileJava FAILED
C:\Users\Marissa\MCreatorWorkspaces\ympossible_mod\src\main\java\net\mcreator\ympossiblemod\entity\renderer\KyuremendRenderer.java:98: error: variable left_arm is already defined in class Modelcustom_model private final ModelRenderer left_arm;
^
C:\Users\Marissa\MCreatorWorkspaces\ympossible_mod\src\main\java\net\mcreator\ympossiblemod\entity\renderer\KyuremendRenderer.java:101: error: variable left_hand is already defined in class Modelcustom_model private final ModelRenderer left_hand;
^
2 errors
FAILURE: Build failed with an exception.
* What went wrong:
Execution failed for task ':compileJava'.
> Compilation failed; see the compiler error output for details.
* Try:
Run with --stacktrace option to get the stack trace. Run with --info or --debug option to get more log output. Run with --scan to get full insights.
* Get more help at https://help.gradle.org
BUILD FAILED in 2s
1 actionable task: 1 executed
BUILD FAILED
Task completed in 23 minutes and 7 seconds