The rules of MISRA C:2012 often gets updated with newer releases and a variety of reasons can be responsible for the violation. Please find the below rules for violation scenarios which has been made for the later releases and may be causing violations.
1) If there are identifiers beginning with underscore
2) If a reserved identifier or macro name is declared
Note: The above possible workaround may/may not work for your case.
In case you only expect to remove the warnings, you can always uncheck rules in the Coding Rules & Code Metrics in the configuration pane. Follow the below steps:
1) Open configuration pane
2) Click on the edit button as seen in the screenshot in red
3) Go to let's say rule no 21.2 and uncheck it as shown in screenshot in red
Here is an attached link for the same.
The above remove warnings can also be unchecked for other rule violations if required.