Task Sequence hangs with "Program Started" and TSAgent.log says "Task Sequence Manager could not get active request info"

[Snakebyte]

Need some help here. I have a medium sized SCCM 2012 environment, single Primary Site server, 5 Secondary Site servers. For the most part, everything works very well, with the exception of task sequences. In most cases, on the initial push of a task sequence, around half will "stall" with a status of running and "Program Started", and go no further. This happens across the board, and to no particular site, subnet, boundary, device type, OS, etc. When I say there is no commonality, I mean there is none that I can find, except that the machine stalls at "Program Started".

Couple other notes:

• Content in most all cases is downloaded without issue, and actually present in the appropriate CCMCACHE folder
  
• Nothing is listed in SMSTS.log. When I say nothing, the log will usually not even showing having been updated since the last task deployment
  
• The machine is pingable, online, with a current client, and recent Heartbeat DDR
  
• Other items (updates, etc) work on the system
  
• I have tried with, and without a maintenance window. Without a maintenance window, I ensure that "Software Installation" and "System restart" option outside maintenance window are both checked
  
• All Distribution Points have current package version
  
• The task shows up in CCMEXEC.log
  

• Notifying endpoint 'execmgr' of __InstanceModificationEvent settings change on object CCM_SoftwareDistribution.ADV_AdvertisementID="HLP20103",PKG_PackageID="HLP00094",PRG_ProgramID="*" for user 'S-1-5-18'. CCMEXEC 7/8/2014 7:40:43 PM 2128 (0x0850)
  

• The only real errors I ever find are in the TSAgent.log file an are as follows:
  

There are no locations for this program TSAgent 7/8/2014 10:05:51 PM 3408 (0x0D50)

Task Sequence Manager could not get active request info. code 80004005 TSAgent 7/8/2014 10:05:51 PM 3408 (0x0D50)

Failed to get the details of the execution request. code 0x80004005 TSAgent 7/8/2014 10:05:51 PM 3408 (0x0D50)

Task Sequence Agent could not get active request info. code 80004005 TSAgent 7/8/2014 10:05:51 PM 3408 (0x0D50)

Error initializing TS environment. Code 0x80004005 TSAgent 7/8/2014 10:05:51 PM 3408 (0x0D50)

Task sequence launcher advertisement failed!. Code 0x80004005 TSAgent 7/8/2014 10:05:51 PM 3408 (0x0D50)

CTSAgent::Execute - Failed to launch Task Sequence manager. TSAgent 7/8/2014 10:05:51 PM 3408 (0x0D50)

On subsequent deployment attempts (third party tools that "redeploy" a deployment) most will succeed, but again, several will hang at the same screen. After several "Re-Deploys" I can usually get to 100%.

Initially, I thought the issue was with the destination OS (2009 POS...I know I know, not my choice), but I've seen the same issue on Win 7 machines with all the same symptoms. The system continues to work normally until such time as you "re-deploy" the app. Have tried reboots to fix to no avail.

Open to thoughts and help here...Please!!!