Please try to install latest sep 12.1.6 client.
in SEPM 12.1.6 BSOD issue are resolved.
Blue screen appears on SEP client machines
Fix ID: 3584396
Symptom: Symantec Endpoint Protection client computer experiences a blue screen error with BugCheck 50.
Solution: Resolved an issue with a change in the SRTSP (AP) module that caused the blue screen.
Blue screen error after upgrading SEP
Fix ID: 3649959
Symptom: A blue screen occurs with BugCheck 3b on Symantec Endpoint Protection client, which points to a SymEFA component.
Solution: Fixed a performance issue which caused the blue screen.
Blue screen error with bugcheck BAD_POOL_CALLER (c2) caused by SYMTDI.SYS
Fix ID: 3525860
Symptom: You see a blue screen error due to unsynchronized access to the disconnect data block, which attempts to deliver the same disconnect twice and delete the block twice.
Solution: Changed to use interlocked exchange to access the data
Bugcheck 0x19_20 BAD_POOL_HEADER referencing Iron64.sys
Fix ID: 3570942
Symptom: In Symantec Endpoint Protection 12.1.2.1 (12.1 RU2 MP1), a blue screen error occurs in Iron64.sys with BAD_POOL_HEADER check code.
https://support.symantec.com/en_US/article.TECH230558.html