Not handling embedded carriage returns which should allow overwriting of previous characters.
Recreated this problem with 2.16 on cygwin, macos, and debian.
Simple examples:
$ echo -e 'abc\r123'
123
$ echo -e 'abc\r123' | ansifilter
abc123
$ echo -e 'abc\r12'
12c
$ echo -e 'abc\r12' | ansifilter
abc12
Edit: corrected output of last command
Edited by Dwaine Gonyier