Not able to populate retained earning account in ledger setup in 12.2.3 - "Please choose an existing combination"

Issue:

Not able to populate retained earning account in ledger setup.
First time Create button is set, it displays the error message: Please choose an existing combination
Then pressing the Create button does nothing.

STEPS
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The issue can be reproduced at will with the following steps:
1. Setup-->ASM-->Ledger


Solution:

To implement the solution, please execute the following steps:

1. Download and review the readme and pre-requisites for Patch:18123067>:R12.FND.C

2. Ensure that you have taken a backup of your system before applying the recommended patch.

3. Apply the patch in a test environment.

4. Confirm the following file versions:
KeyFlexfield.java 120.12.12020000.3
You can use the commands like the following:
strings -a $JAVA_TOP/oracle/apps/fnd/flexj/KeyFlexfield.class | grep '$Header'

5. Bounce the instance after applying the patch

6. Re-test the issue.

7. Migrate the solution as appropriate to other environments.