Hi,
not sure that I understand it correctly and would like ask to be sure:
If you choose “System Managed” then Windows will create in your case a 65GIG pagefile ??
If so, this should not happen. The default size in your case should be 8~9GIG and this is because the rule behind ( /8 ). The maximum size depends on your free disc space.
If you see a 65GIG pagefile, then maybe there was a application with a memory leak. I had this one time with DCS in multiplayer where it fills completely the RAM in a few seconds and then of course my pagefile runs out too. But, here you can also see that my max “safe” me in these situation too. There is no “game” which consume these amount of memory and so it was only 4GIG filled instead 65GIG filled on my ssd.
I still can recommend for 64GIG users a manual setting like:
Minimum: 1024 and Maximum: 4098/8192/… ( jsut how you feel good, but you will usually not need it )
Or… wait.. I get an idea…
Did you have crash/memory dump creation enabled ??
If yes, this might explain the huge pagefile in System Management setting, because pagefile is just necessary for that. If you choose “complete memory dump”, then the pagefile is bit more in size as your amount of RAM. With “auto memory dump” the increasment of pagefile will happens after some( or one) crashs only ( cant remember all rules 
). Mostly you not realy need a full memory dump. Just choose “the mini dump” setting.