Hi Vanessen,

Thank you for your post.

First of all I want to convince you that this message doesn't mean that somebody made changes. 

It appears if Salesforce has changed something in the formatting of the just built files, for example spaces or extra line break in the end of the file. In this case, you get an opportunity to select which view of the file you want to see in your editor: with you formatting or with that one which is present on Salesforce. 

We are going to work on the issue that this message appears after the each Build process.

Regards,

Kate

The same thing happens to me but if I reload the file when prompted, all code changes are reverted.

Hi,

Thank you for your post.

We have been faced with this issue and our team is going to investigate it.

I kindly ask you to tell me if any test was run at the same time inside IDE?

As a workaround, please click 'Ctrl+z'.

Please let me know if this action won't help you to return your changes.

Thank you,
Kate