I am trying to control a ketron evm with pa5x , but I can't sync tranpose. Anyone knows if it is a bug ?

AFAIK, there’s no universal MIDI code for ‘transpose’.

However, if you hit transpose on the Korg, the NOTES you are sending from it (via MIDI OUT) SHOULD already be transposed. So if you are running the EVM from the PA5x, you should only have to transpose the master keyboard.

What are you doing that it DOESN’T respond correctly?

Right. Can you connect a laptop or iPad to determine what's actually coming out of the Korg? Did you carefully review all of the Korg's MIDI options to determine whether transpose is being applied to MIDI out? That's where I would start.