Do you use your emergency brake a lot? I`m assuming these brakes are disc. . Either way, check the moveability of your e-brake cable, and mebe shoot some lithium grease inside the casing, and work it in. Might be good to check brake quality and ebrake hardware with the wheel off... Other than an actual ABS malfunction with the pump, which you`d no doubt feel pulsing, my bet is the ebrake. .
good luck
-j