What happens when you set Windows to let it manage the pagefile (and with an SSD, that is most optimized way to do it):
You mention the SSD is quite small so why use 16gb of it for a paging file. Well, the answer is because the paging file is the most important file to perform as fast as possible in order to increase the performance of Windows in general. So the real question is, if you have 16 GB of free space available on the SSD, then why would you NOT want it to be used for the paging file?
My guess is that something happened to damage the paging file on the HDD and once you let Windows manage it (and Windows will put it on the SSD only because that is the best place for it), you can look for the hidden and system .sys files on the root folder of the HDD and delete them.
Mine are on the SSD, so you would want to look for them on D: drive (or whatever drive letter the HDD is on your system) but here is an example:
Without an SSD it was optimal to set a fixed size for the pagefile to avoid it becoming fragmented. With an SSD that is no longer true or applicable.
Volume in drive C has no label.
Volume Serial Number is 1ABD-1D37
Directory of C:\
10/29/2015 11:18 PM 400,228 bootmgr
10/29/2015 11:18 PM 1 BOOTNXT
01/06/2017 02:43 PM 6,635,855,872 hiberfil.sys
01/03/2017 02:54 PM 2,550,136,832 pagefile.sys
01/03/2017 02:54 PM 16,777,216 swapfile.sys
5 File(s) 9,203,170,149 bytes
0 Dir(s) 417,831,768,064 bytes free