Updating web.config through SPWebConfigModification updates last modified date for all webapp web.config files

Hi,

I have tried updating web.config entries through SPWebConfigModification class. We are targeting for single web application. This updates value fine in the web.config for the specific web application. 

But what happens is, For every web application, the web.config file last modified date is updated. This eventually recycles app pool for that web application. It had just refreshed last modified date, but web.config file values are not touched. When we follow this approach, it brings down other web applications too, even though we targeted for a specific web application.

webApp is the specific webapplication object.

webApp.Farm.Services.GetValue<SPWebService>().ApplyWebConfigModifications(); also didn't help.

webApp.Parent.ApplyWebConfigModifications() also didn't help.

Did any one get it to work in another approach or is it a bug with SPWebConfigModification class.

Thanks,
Prasanna B J.