stevet/aptgrade

0 upgraded, 0 newly installed, 1 to remove and 0 not upgraded.
                                                              After this operation, 58.4 kB disk space will be freed.
                                                                                                                     (R(Reading database ... 292436 files and directories currently installed.)
Removing libfl2:amd64 (2.6.4-8.2build1) ...
Processing triggers for libc-bin (2.39-0ubuntu8.6) ...

Notice the "(R(Reading database ... " above. Not sure why that was having issues. I have some of the actual output:

[/usr/bin/apt-get autoremove -y]
Reading package lists...
Building dependency tree...
Reading state information...
The following packages will be REMOVED:
  libfl2
0 upgraded, 0 newly installed, 1 to remove and 0 not upgraded.
After this operation, 58.4 kB disk space will be freed.
(Reading database ... ^M(Reading database ... 5%^M(Reading database ... 10%^M(Reading database ... 15%^M(Reading database ... 20%^M(Reading database ... 25%^M(Reading database ... 30%^M(Reading database ... 35%^M(Reading database ... 40%^^M(Reading database ... 45%^M(Reading database ... 50%^M(Reading database ... 55%^M(Reading database ... 60%^M(Reading database ... 65%^M(Reading database ... 70%^M(Reading database ... 75%^M(Reading database ... 80%^M(Reading database ... 85%^M(Reading database ... 90%^M(Reading database ... 95%^M(Reading database ... 100%^M(Reading database ... 292436 files and directories currently installed.)
Removing libfl2:amd64 (2.6.4-8.2build1) ...
Processing triggers for libc-bin (2.39-0ubuntu8.6) ...

There were many lines overwritten by the \r (carriage return). I tried creating an output program that would do exactly the same thing, but it didn't seem to cause any issues with output. (apt-get output issue?)

I'm not sure where the bug is here. Try using aptgrade --output so I have sample output files to debug.

#2 Visual output issue.