I own both TS-451 and HS-251. Three different USB3 HDDs leading to frequent reboots of the whole NAS when being accessed (= copying files to the HDDs using the share provided by the QNAP NAS).
Seagate Expansion Desktop 4TB (STBV4000200)
Seagate Backup Plus HUB 6TB (STEL6000200)
Seagate Expansion Desktop 6TB (STEB6000403)
For me this problem applies for all newer firmwares. The last version working stable is 4.3.4-0644. Both NASes show the same behaviour with these drives and newer firmwares.
