24 VDC PS supplying 25 V?
As a general rule, 1 volt in 24 (4% error) is entirely normal. But it all depends on the power supply specifications.

A very common tolerance for power supplies is +/- 10%, which would be +/- 2.4 volts. A fairly tight spec would be 5%. However, for non-adjustable precision supplies you can find 1% units although that is rare. It is a good idea, especially for high-current units, to provide an open-circuit output slightly on the high side to allow for the inevitable voltage drop in the output wires.