This is the first time I've observed this, but today I was unable to cap Theta on Tourmaline. The laser beams around the point did turn red, indicating that I was in the cap area, but the HUD would not respond to the cap and the beams would not go green even after a long time standing inside. Everything else, including caps to other points, were working fine. I even returned back to Theta to try again but it would still not respond. And no, there were no enemy mechs nearby.
Here's a screen shot I took: