1. The tape lights appear to have been installed so the inside edge of the cove (or something inside the cove) blocks the light emitted by the strip. You need to get a ladder and look at how the tape lights are fitted into the cove to determine what's blocking the light.
2. Perhaps whoever installed the tape lights overlapped the two strips at the corner. He could have used an angle connector like this:

Its just mounted wrong, should be closer to the middle- front edge. its loosing light to the front and bouncing light off the wall at the back. and yes I would also agree they didnt but joint the corner but rather ran a solid line. I would get a ladder and look.

Finally got a chance to check, there are gaps between the strips in the corners and they are in the middle front of the cove. What should get changed?

Thanks. So raising or blocking the angle of the tape light should get rid of the sharp fall off of light on the ceiling. Have to figure out the exact distance to eliminate the crossover.

Another idea: Instead of mounting the tape light inside the cove, mount it on the wood, facing the ceiling. Just make sure the tape lights wouldn't be visible from below (the wood does look wider than the tape lights so that shouldn't be a problem). Use angle connectors (shown in the earlier photo) to connect the sections of tape lights together.

Experiment with positioning the tape lights before attaching them permanently.

covers for the tape lights really helped. no sharp fall off or cross over of lighting.

So you left the tape lights as they were and put some kind of cover/diffuser over them?

Yep. Was surprised it worked as well as it did. Here is a photo

Oh yeah, that's much better...and far less work than having to fool with the tape lights themselves.