Before AESH had 'export', added by the AESH upgrade, the CLI created 'set' to handle variables.
With the upgrade, the commands overlap and interfere.
Using commands, 'set name=value', and then 'echo $name', AESH will now search it's 'export' list for the variable. Which doesn't exist, so the variable is replaced with nothing. By the time the input processing gets to the CLI to search the 'set' variable list, the '$name' part of the string has been removed from the line by AESH's export processing.
Export didn't exist before the upgrade, so disabling it doesn't cause problems.
This was missed by the tests because part of the CLI actually bypasses AESH and most of the tests use that method.