[Matteo Bertozzi]

Thank you for both of your answers. The problem was weird, basically in some projects the path of the masks showed up and in others it didn’t and the weirdest thing was that the masks worked fine on only one or two sequences in projects with four or five sequences inside them.
Anyway the problem now is solved thanks to an Adobe staff memeber over at the Adobe Forum. I’ll copy and paste his answer in case somebody runs into the same issue.

Try the following steps,

1. Create a new project in Premiere Pro CC 2017, Import the project file(.Prproj) created in CC 2015 into it using File > Import & check the mask edges.

If issue persists,

2. Go to the following location in the machine
In Windows, C:\Users\UserName\Documents\Adobe\Premiere Pro\11.0 (Or)
In Mac, Documents > Adobe > Premiere Pro > 11.0
Rename the 11.0 folder to Old_11.0

Launch Premiere Pro, Create a new project(do not open Old projects)
In Menu bar, Window > Workspace > Uncheck Import Workspace from Projects.

Open the old project & check the Mask Edges.

The second solution worked, I still have no idea why I had that problem and why the second solution worked but now everything works fine so I can’t complain.

Thanks again for you answers and I hope this helps people with the same issue.