Running systemctl list-units | grep -i sym on a system with Symantec Endpoint Protection for Linux shows that, while autoprotect.service is loaded and active, it exited. The same is not true for all other Symantec services, which are shown to be loaded, active and running.
[root@symantec]# systemctl list-units | grep -i sym
autoprotect.service loaded active exited LSB: Symantec AutoProtect Modules
rtvscand.service loaded active running LSB: Symantec AntiVirus Scanner
smcd.service loaded active running LSB: Symantec AntiVirus Scanner
symcfgd.service loaded active running LSB: Symantec AntiVirus Configuration Server
Symantec Endpoint Protection for Linux 12.1 RU5 or higher
autoprotect.service is a systemd stub for our autoprotect init script (normally found in /etc/init.d/autoprotect). When starting, it is responsible for going through the list of available autoprotect modules, finding out which ones are candidates for attempting load and loading them. When stopping, it is responsbile for disabling autoprotect. Once it finishes, there is nothing left running in user space, so it makes sense that systemd (as shown by systemctl) reports it as “exited” instead of “running”.
This is 'by design'. Please refer to the Cause section for more details.