This happened once to me, too. No apparent reason. Switched off the set with the main switch and unplugged it from the mains for 30 sec and the stanby-light returned to 'normal'.
BV 10, Avant 28 DVD, VX 7000, BC 3000, BL8000, BL6000, MX 4002, Beoport, BL4, LC2, BeoCom6000, BeoCom1401