Declination stability problem

• Date and time: Oct. 15, 2017 [3:15 UT − 3:28 UT]
• Exposures: 5 × 80 s
• RA, DEC: 2h 43m 56s, +12d 19m 13s
• Telescope position: Reverse (West of the pier), South is Up
• Differential tracking: 0.710 "/min, P.A. 264 deg
• Azimuth, Elevation: 226 deg, +35 deg