Getting Error : java.lang.IllegalArgumentException: Can not set io.appium.java_client.MobileElement field com.elliemae.qa.encw.pipeline.LoanPipelinePage.readOnlyNoBtn to com.sun.proxy.$Proxy26

//Parent Class
public class ParentPageObjectClass {

WebDriver driver;   
WebDriverWait wait;

public PipeLinePage(WebDriver driver) {
    this.driver = driver;  
    PageFactory.initElements(driver, this);        
}

//Child Class
Public class ChildPageObjectClass extends ParentPageObjectClass {

AppiumDriver<MobileElement> driver;  

public LoanPipelinePage(AppiumDriver<MobileElement> driver) {
    super(driver);
    this.driver = driver;
    PageFactory.initElements(new AppiumFieldDecorator(driver, ofSeconds(5)), this);       
}

@AndroidFindBy(accessibility = PipelineConsts.LOAN_READONLY_NO_BTN)
@iOSXCUITFindBy(accessibility = PipelineConsts.LOAN_READONLY_NO_BTN)
public MobileElement readOnlyNoBtn;

I am automating Hybrid app where i have existing webDriver page classes & want extend those within appium page object clasess so i can use the existing methods. insted of creating 2 seperate classes i want to extend the old page object class

but getting below error while creating object of Child class. Above is the code snippet
Error is in PageFactory.initElements(driver, this); of parent class
Error : java.lang.IllegalArgumentException: Can not set io.appium.java_client.MobileElement field com.elliemae.qa.encw.pipeline.LoanPipelinePage.readOnlyNoBtn to com.sun.proxy.$Proxy26

If i dont extend class it works fine
Also if i dont use @@AndroidFindBy/@iOSXCUITFindBy annotations it works fine

Can some one please help me

You could also try v8-beta of the client, which has better support of newer java releases