Disputing (dialegomenon). Simply conversing, discussing, arguing, and then disputing, common verb in old Greek and in N.T. (especially in Acts).
Stirring up a crowd (epistasin poiounta ochlou). Epistasis is a late word from ephistēmi, to make an onset or rush. Only twice in the N.T., 2Co 11:28 (the pressure or care of the churches) and here (making a rush of a crowd). The papyri give examples also for “onset.” So Paul denies the two charges that were serious and the only one that concerned Roman law (insurrection).