Harmony v3 and Input Capture on Curiosity 2.0. I can't understand. (LeMomo)

I am trying to use the Input Capture on my Curiosity 2.0 board and I get a behavior I can't understand.My IC1 Capture handling routine looks like:static void myICAP_1_Handler() {
cap = ICAP1_CaptureBufferRead() - valprv;
TMR3 = 0;
OUT_..