The continued presence of the obsolete file /etc/apt/apt.conf.d/05aptitude may be preventing the proper functioning of the 'keep the most recent two kernels' behaviour introduced through the automatically-generated /etc/apt/apt.conf.d/01autoremove-kernels and associated kernel postinstallation script /etc/kernel/postinst.d/apt-auto-removal
The continued presence of the obsolete file /etc/apt/ apt.conf. d/05aptitude may be preventing the proper functioning of the 'keep the most recent two kernels' behaviour introduced through the automatically- generated /etc/apt/ apt.conf. d/01autoremove- kernels and associated kernel postinstallation script /etc/kernel/ postinst. d/apt-auto- removal