No, this has not happened yet: until Jon Ericson, all former Community Managers who are no longer employed at the company ceased to be moderators after leaving.
Here are the CMs, past and present, ordered by period of service. This list does not count members of the support team as part of the group of CMs, although the answer is the same even if you do (at time of writing). (Note: current employees are not permitted to serve as volunteer moderators while employed, regardless of their job in the company.)
Robert Cartaino - no
Was never a community moderator
No longer employed by Stack Exchange
Rebecca Chernoff (also used name "rchern" while a CM) - no
Was a community moderator (Web Applications)
No longer employed by Stack Exchange
Did not return to community moderator status
Shog9 - no
Was never a community moderator
No longer employed by Stack Exchange
Dori - no
Was a community moderator (Apple)
No longer employed by Stack Exchange
Did not return to community moderator status
HedgeMage - no
Was a community moderator (Parenting)
No longer employed by Stack Exchange
Did not return to community moderator status
Grace Note - no
Was a community moderator (Gaming)
No longer a CM, but still employed by Stack Exchange
Aarthi - no
Was never a community moderator
No longer employed by Stack Exchange
Adam Lear - no
Was a community moderator (Stack Overflow, Software Engineering, Literature)
No longer a CM, but still employed by Stack Exchange
Tim Post - no
Was a community moderator (Webmasters, Stack Overflow)
No longer a CM, but still employed by Stack Exchange (although continues to act in a CM-like way as Community Evangelist and previously Director of Community Strategy)
Jon Ericson - special case
Was a community moderator (Biblical Hermeneutics)
No longer employed by Stack Exchange
Has been reinstated as a community moderator and also the question is really about everyone except him
Gabe - no
Was never a community moderator
No longer a CM, but still employed by Stack Exchange
Pops (used name "Popular Demand" until just after signing on as a CM) - no
Was never a community moderator
No longer employed by Stack Exchange
Ana - no
Was never a community moderator
No longer employed by Stack Exchange
jmac - no
Was a community moderator (Workplace)
No longer employed by Stack Exchange
Did not return to community moderator status
hairboat (also used name "Abby T. Miller" and "abby hairboat" while a CM) - no
Was never a community moderator
No longer a CM, but still employed by Stack Exchange
Nicolas Chabanovsky - no
Was never technically a community moderator, but, as the founder of hashcode.ru (the site that became Stack Overflow in Russian), held a somewhat comparable role there
Current CM
Taryn (used name "bluefeet" while a CM) - no
Was a community moderator (Stack Overflow)
No longer a CM, but still employed by Stack Exchange
Juan M - no
Was never a community moderator
Current CM
JNat - no
Was a community moderator (Anime & Manga)
Current CM
Catija - no
Was a community moderator (Arts & Crafts, Interpersonal Skills)
Current CM
Cesar M - no
Was never a community moderator
Current CM
And finally, an honorable mention:
animuson - no
Was a community moderator (Stack Overflow)
Was also never a CM, but acts in a CM-like way as a member of the support team
