Do back/front focus problem happen more often at 28mm or 400mm?

[maisatomai]

As above.

 

[one eye jack]

Checking Your Camera for Front Focus or Back Focus. | Camera Light & Lens Forum – News

PENTAX DSLRs: Front or Back Focusing Problems? Free test (Lens Alignment) charts for Pentax, Nikon, Canon, Sony, Olympus.

This is a question of wear and tear or aging electronics.You will notice it less if at wide angle eg. 28mm because depth of field is greater and more noticeable if at telephoto again because of shallower DOF.Some newer high end camera have in camera adjustment.
If not need to visit the service center.Above are links to check the problems diy.

 

[Octarine]

The deep depth of field at 28mm and the shallow depth of field at 400 ... which one will reveal a focusing error? Use the online DOF calculators the check the results.