So I pulled the drive, added a 4tb to maintain parity in the meantime. That drive is using the same connections/cables as the 10TB was and it has had no problems. Rebuilt parity fine and no errors all week.
I connected the 10TB in question to my PC and ran it through some burn in tests and what not and its passed everything. SMART says its good, WD diagnostics tool says its good.
I'm thinking about buying some new cables anyway, but do you think theres any harm in re-adding the 10TB in question to server?