Rolling back on a hill?

I have owned a 2016 TRD for 1 month; on my first trip to RI (surf fishing), while stopping at a stop sign on an incline had the vehicle roll back while transmission in drive. Made a strange grinding noise as it rolled back slightly -only about a foot or so before i stepped on gas to proceed through intersection. No automatic transmission that Ive owned ever rolled back on a hill--bringing it back to dealership in a day or two to explain to them. What say you guys?

Thanks in advance
Plugman

 

Just your abs trying to stop you from rolling back. Completely normal.

 

Did you catch anything??

HAC (Hill-start Assist Control)
http://www.toyota-global.com/innova...echnology/technology_file/active/dac_hac.html

 

Yep. Was just about to say the same thing. Surprised me the first time it happened. Mine will bark at me if I roll back without stepping on the break pedal first, like a rolling stop waiting for my garage door to open. If I use the break pedal, like at a stop sign, it'll hold and not roll back. Seems normal from what I've read.