I'm running SQL Server Standard 2014 (12.0.2000.8 RTMStandard Edition (64-bit)) and I run a daily SSIS job. The Job calls two child processes for each customer (21 customers) and it runs between 20 to 60 minutes a day. I've noticed that ISServerExec.exe is still running after the process completes and I've seen 20+ copies of the program running in memory all taking over 1GB of memory.
I'm using the Execute Package Task to call the child processes.