I don’t think is that HDD power issue. We had test the uTrack-X32 with the same Toshiba Canvio drives we were able to make more than 48hours recording with no problem.
From your description I still thinking about the following causes:
-Loose connection or cable, but as you said you tried with different drives I don’t think all of your cables are broken, please try to use the shortest as possible cables.
-Clocking issue –> please do a test recording on a stand alone device where no router, no noting connected only the X32 card then start the recording.
-To make sure that HDD powering issue, it would be nice to try with an SSD drive.
At least we can step one step further is that networking , clocking or power/drive related issue.