Are you sure that what you're seeing isn't a Trace Reference, with the color of reference set to 'original color'? The screenshot of your 2nd Floor shows that trace/reference is definitely active (the red slider 'grips' on all four sides).
Also, please add a Signature or mention your version of AC when you post. The screenshot with tabs tells us that you're on AC 19 ... but without the screenshot, I would have imagined you were in an older version that wasn't compatible with El Capitan. 😉
One of the forum moderators • AC 26 USA and earlier • macOS Ventura 13.2.1, iMac Pro 10-Core, Radeon Pro Vega 64