TMK 700B measurement depends on placement

[taydin]

I have acquired a TMK 700B analog multimeter and have tried measuring DC voltage with it. What I'm seeing is that the measured value depends on whether the multimeter is placed horizontally or vertically on the bench. When measuring 12 V, the discrepancy is about 1 V. I don't think this is normal because the stated accuracy of this multimeter is 2%. It is also out of calibration, which I will do soon, but this problem with the alignment shouldn't be related to calibration or the accuracy.

When looking at the manua of it, there isn't any requirement to use this multimeter in the upright position or vertical position, so I'm not sure what's going on with this. Anybody can give ideas?