'/var/lib/dpkg/tmp.ci/md5sums': Is a directory

Trying to update Ubuntu 20.04.
I tried the solution in Cannot upgrade rsync following distribution upgrade to 20.04LTS

I tried to # sudo apt autoclean and receive warnings for packages:
dpkg: warning: files list file for package 'linux-hwe-5.8-headers-5.8.0-49' missing; assuming package has no files currently installed that I assume is normal after autoclean.

Corrently, I get the below error. Same result for sudo apt-get install --reinstall rsync

# sudo apt upgrade
...
dpkg: warning: files list file for package 'linux-modules-5.4.0-67-generic' missing; assuming package has no files currently installed<br>
(Reading database ... 605012 files and directories currently installed.)
Preparing to unpack .../libwebkit2gtk-4.0-37_2.34.4-0ubuntu0.20.04.1_amd64.deb ...
Unpacking libwebkit2gtk-4.0-37:amd64 (2.34.4-0ubuntu0.20.04.1) over (2.34.1-0ubuntu0.20.04.1) ...
dpkg: error processing archive /var/cache/apt/archives/libwebkit2gtk-4.0-37_2.34.4-0ubuntu0.20.04.1_amd64.deb (--unpack):
unable to install (supposed) new info file '/var/lib/dpkg/tmp.ci/md5sums': Is a directory
Errors were encountered while processing:
 /var/cache/apt/archives/libwebkit2gtk-4.0-37_2.34.4-0ubuntu0.20.04.1_amd64.deb
E: Sub-process /usr/bin/dpkg returned an error code (1)

I also tried to install libwebkit2gtk individually and endup with the same result.

# sudo apt-get install libwebkit2gtk-4.0-37
...
 '/var/lib/dpkg/tmp.ci/md5sums': Is a directory
...
E: Sub-process /usr/bin/dpkg returned an error code (1)