UPDATE: I have tested the same configuration with TMOS v12.1.3.7 and everything went fine. The cluster was successfully formed and configuration synced. Also I have checked v14.0.0.2 - configuration is not synchronized between devices. What I have spotted is that the output from "tmsh run /cm watch-devicegroup-device" and other "tmsh run /cm watch *" commands state "Incompatible Version", despite both appliances use the same TMOS SW version. So it seems currently neither v13.x nor v14.x are able to form DCS and sync configuration successfully.
Below reside logs from a standby virtual appliance:
Oct 28 16:47:19 bigiptest1 notice mcpd[4508]: 01070430:5: end_transaction message timeout on connection 0x5c204548 (user %cmi-mcpd-peer-10.3.0.201)
Oct 28 16:47:19 bigiptest1 notice mcpd[4508]: 01070418:5: connection 0x5c204548 (user %cmi-mcpd-peer-10.3.0.201) was closed with active requests
Oct 28 16:47:19 bigiptest1 notice mcpd[4508]: 0107143c:5: Connection to CMI peer 10.3.0.201 has been removed
Oct 28 16:47:19 bigiptest1 notice mcpd[4508]: 01071432:5: CMI peer connection established to 10.3.0.201 port 6699 after 0 retries
Oct 28 16:52:22 bigiptest1 notice mcpd[4508]: 01070430:5: end_transaction message timeout on connection 0x5c204548 (user %cmi-mcpd-peer-10.3.0.201)
Oct 28 16:52:22 bigiptest1 notice mcpd[4508]: 01070418:5: connection 0x5c204548 (user %cmi-mcpd-peer-10.3.0.201) was closed with active requests
Oct 28 16:52:22 bigiptest1 notice mcpd[4508]: 0107143c:5: Connection to CMI peer 10.3.0.201 has been removed
Oct 28 16:52:22 bigiptest1 notice mcpd[4508]: 01071432:5: CMI peer connection established to 10.3.0.201 port 6699 after 0 retries
Altocumulus