When a command is as long as the terminal width, if some completion occurs at the beginning of the command, the cursor jumps at the end and behave strangely.
eg (from aesh example)
Type (number of 'c' char according to terminal width):
[aesh@rules]$ long-output --prompt cccccccccccccccccccccccccccccccc
Then move the cursor at the end of long-output.
Remove the ut characters with backspace.
Press TAB ==> cursor jumps.