After upgrading to 8.6 RU2 and adding support to WinPE 11 (per KB https://knowledge.broadcom.com/external/article/228797/)
Any unknown client machine booted into automation and picking up the Initial Deployment job containing SWD task would fail with the message that "Software Management Solution Plug-in is not installed"
WinPE 11 is detected as production OS, thus we require any production OS to have Software license allocated in order to execute SWD tasks.
Deployment Solution 8.6 RU2
The issue has been identified as a defect and will be resolved in the 8.6 RU3 release.
Meanwhile, as a workaround you can apply the following updated SQL Stored procedures against the Symantec_CMDB database to allow unknown clients booted into WinPE 11 preboot environment to process jobs containing SWD tasks.
NB. Broadcom Technical Support Team always highly recommends to make a full backup of CMDB database before making any changes or updates.