Seem to have this problem myself. Been more noticeable the last few mornings (as it's been colder at night) only have a two mile drive to work and it really only happens for the first minute of driving it is more annoying than anything. Car is a bit of an unknown quantity to be fair. Test drove it and HAD to have it Scorpion exhaust fitted but haven't even checked to see if its got a panel filter fitted and no idea if it's been mapped
I've got that exhaust and a panel filter too. Also have the decat pipe and the flat spot was awful but didn't notice the kangaroo'ing get any worse. A map has got rid of the flat spot completely though.