This sounds like you or someone on your team has edited the styles for your project.
The most likely location of this change would be in your project folder, in a file called custom.sty. If you open this file in a text editor you can search for Marker ip. Hopefully in the section under that line there will be a line that says \Color 16711680 (probably with a different number). Delete that line, save the document as plain text, and restart PT.