Is this happening to other users as well? do you know if the OOTB admin user is having this problem too?
Is this happening in other language different than English?
Do new RTs have the issue too? happening to a specific RT? (RT stands for requests type)
Did you try recompiling all the jsp files in your PPM server? with just stop PPM and delete the work and temp folder from all your nodes and then starting teh server again you will recompile all the files involved in PPM.
Also, what is your current PPM version?
Lets us know so with those details we will be able to help you better.
That may be because of any trigger in the database. When you save the request type then the trigger would check for the particular condition, if that is satisfied then it must be updating the Radio button from Yes to No.
Check the Triggers in database. That might be possible cause for this situation. Go to database and execute below query..
Say the paramter for Radio button is Parameter30..
SELECT * FROM USER_SOURCE WHERE TEXT LIKE '%PARAMETER30%';
Check all the Database Objects in the result. If there is any trigger then open and see if that's causing this issue.
PS: If the post resolves your issue, please give KUDOS and mark it as Accepted Solution.