Could be the clutch is glazed
It sounds like a slightly slipping clutch, It could be glazed.
Other then that it could be the dual mass crap pressure plates they use now a days to cushen the torque impact on the drive train. ( Not likly but possable)
I vote for the bad clutch
2012-candy red- V-6 MCA, Automatic Trans. CFM Valve cover breather. MMD blackTail light trim.Magnaflow axle back street mufflers, JLT oil catch can.MMD hood struts.
Airaid Cold Air intake. red caliper covers, 3.7L performance engine cover, Flat black hood spears.Boss 302 strut brace, CDC rear panel, Trunk Cargo net,--Dash carpet cover,
Viser stickers to cover ugly yellow warning crap,Aluminum driveshafft and Swarr Bar.