ProDOS: Problems using the CONVERT program in 80 columns

The CONVERT program malfunctions if it is executed when the 80 column display is active. The top lines are scrambled and ProDOS date and prefix aren't displayed.
Here are two possible workarounds:

1. Exit from the 80-column card firmware with ESC-CTRL-Q, then execute CONVERT.
2. Enable 40-column display with ESC-4, then execute CONVERT.

In both cases you restore the 40-column screen, and the program works correctly.

This situation occurs in the following configuration:

1. ProDOS Developer's Disk V 1.0 C
2. ProDOS system file dtd 01.11.83
3. Convert program version 1.1, dated 01.11.83
4. System configuration: Apple IIe and Extended 80-column card.
Published Date: Feb 18, 2012