[doublepost=1498228536][/doublepost]Quick Question, I know the earlier Macs like the 2011 can be Finicky with Ram Upgrades. Do you have a PN or link for the 16GB of ram running in your 13" MBP 2011?
Go to crucial.com and download the scanner. It will then show you the type of memory it takes. I upgraded my 2011 to 16GB of RAM I bought off the site and has been working for years.