.Net Framework error thrown on execution of FindChild in TestComplete

Test complete Version : 10.2

When running scripts on my latest version of application, findchild code is throwing .Net framework error "Value cannot be null" in some screens. The same code was running fine in older version of my application.

Observations:

1. The screen where this issue is seen the child nodes takes a lot of time to expand in object browser and we get same error in object browser the first time we try to do the expand of child nodes

Solutions Tried:

1. Delay before findchild code

2. Parent. Refresh method

3. .Net Framework was initially 4.5.2. Updated to 4.6.2 and checked.

4. Set Jit Debugging = True in Machine.Config and Application.Config files

These solution did not help