The fix for WFCORE-1804 was committed here.
It has a side-effect that it disables quote parsing. Now the another fix which does not have the side-effect was committed in aesh. The following line in the previous fix should be removed, when the new aesh version is released (0.66.11 or 12?).

cli/src/main/java/org/jboss/as/cli/impl/CommandContextImpl.java:495

        settings.parsingQuotes(false);

Proposed solution:

1. parse ' and " and display the '>' prompt if ' or " are not escaped (\' or \") and if ' and " are not closed
2. Do not parse the ' and " when they are located in comment (a line that starts with #)