Its across the fence mate , the trackers were on the recon teams ass constantly tracking them through enemy territory.
The trackers will continue to chase and harass you until you deal with them.
The best tactic is to plant mines on your 6 and dog leg every so often to throw them off your trail, or use suppressed weapons to deal with them quietly.
I cant attest to the mortars , through hundreds of play throughs ive only been killed by mortars a handful of times in the campaign missions.