No, this has not happened yet as of the time this answer was originally posted: until Jon Ericson, all former Community Managers who ceased to be employed at the company also 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 (2010–2020)
Rebecca Chernoff (also used name "rchern" while a CM) - no
Was a community moderator (Web Applications)
No longer employed by Stack Exchange (2011–2013)
Did not return to community moderator status
Shog9 - no
Was never a community moderator
No longer employed by Stack Exchange (2011–2020)
Dori - no
Was a community moderator (Apple)
No longer employed by Stack Exchange (2011–2011)
Did not return to community moderator status
HedgeMage - no
Was a community moderator (Parenting)
No longer employed by Stack Exchange (2011–2011)
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 (2011–)
Aarthi - no
Was never a community moderator
No longer employed by Stack Exchange (2011–2013)
Adam Lear - no
Was a community moderator (Stack Overflow, Software Engineering, Literature)
No longer a CM, but still employed by Stack Exchange (2012–)
Tim Post - yes
Was a community moderator (Webmasters, Stack Overflow)
No longer employed by Stack Exchange (2013–2020)
Has been reinstated as a community moderator on Stack Overflow only (not on Webmasters)
Jon Ericson - yes
Was a community moderator (Biblical Hermeneutics)
No longer employed by Stack Exchange (2013–2020)
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 (2013–)
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 (2013–2017)
Ana - no
Was never a community moderator
No longer employed by Stack Exchange (2013–2018)
jmac - no
Was a community moderator (Workplace)
No longer employed by Stack Exchange (2014–2017)
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 employed by Stack Exchange (2011–2021)
Nicolas Chabanovsky - no
Was never technically a community moderator, but, as the founder of hashcode.ru (the network that became Stack Overflow in Russian and Russian Language in Russian), held a somewhat comparable role on those sites
Current CM (2015–)
Taryn (used name "bluefeet" while a CM) - no
Was a community moderator (Stack Overflow)
No longer employed by Stack Exchange 2015–2021)
Did not return to community moderator status
Juan M - no
Was never a community moderator
No longer employed by Stack Exchange (2015–2022)
JNat - no
Was a community moderator (Anime & Manga)
Current CM (2015–)
Catija - no
Was a community moderator (Arts & Crafts, Interpersonal Skills)
Current CM (2018–)
Cesar M - no
Was never a community moderator
Current CM (2019–)
Ayo - no
Was never a community moderator
No longer employed by Stack Exchange (2021–2021)
Rosie - no
Was never a community moderator
Current CM (2021–)
Philippe - no
Was never a community moderator
Current CM (VP of Community) (2021–)
Slate - no
Was a community moderator (Puzzling, Literature)
Current CM (2021–)
Charlotte - no
Was never a community moderator
Current CM (2021–)
V2Blast - no
Was a community moderator (Role-Playing Games)
Current CM (2021–)
SpencerG - no
Was never a community moderator
Current CM (2021–)
Bella_Blue - no
Was never a community moderator
Current CM (2021–)
Salmon_of_Wisdom - no
Was never a community moderator
Current CM (2021–)
Berthold - no
Was never a community moderator
Current CM (2022–)
Dalmarus - no
Was never a community moderator
Current CM (2022–)
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 (2015–)
