Amongst Quite a Few
Some years ago, over central Singapore, in bound Changi, TCAS sprung to life. About 3,000ft over Paya Lebar I initially saw a white circle, quickly followed by amber TFC followed by red RA "Climb" then "Descend" then "Clear of Tfc". All in all about 3 or 4 secs. ATC said "No tfc". Subsequent investigation through the military, disclosed a pair of visiting F106 (IIRC) left Payar Lebar and climbed vertically to FL Astro, passing (mercifully) either side of my 767.