Amy - Welcome to our forum.
Just looking at the picture it doesn’t appear to be a tendon failure. To me it looks like the grout that was placed inside the pocket didn’t bond with the concrete and is popping out, which may be contributing to adverse condition on the tendon. When I blow up the image it gets pixelated. I would have to see it in person to know for sure, your inspector may have seen other signs that aren’t in the attached picture. I assume your inspector recommended having it evaluated by a structural engineer. That would be a good next step.
Most post tension tendon failures can be repaired by a qualified post tension installer. Only you can decide how big of a red flag it is for you. I’ve been a Level 1 & 2 Unbonded PT Installer & Inspector since 2007, so too me it’s not a huge problem but it will have a cost associated with it.
Side note: most tendon failures occur during installation or after a number of years under adverse conditions. Is the house close to the gulf?
You can also find additional information about post tensioning at https://www.post-tensioning.org/
Hope this helps have a great day!