but it can open correctly in Photoshop(solved)
solution:you can't set link refresh the broken link to no link then save, if now open the file with affinity you will get a not correct one , but in photoshop all seems still working
(if you create new blank image with Photoshop and place the broken-linked PSD with smart object inside you will get an error said link broken ,please relink the missing PSD file)
so it's the Broken PSD made the smart object function of Affinity Photo no-working
BTW: how to export the presets file in My Preset list or how to copy it out and reinstall correctly to 1.9(Pre is 1.8.5.703)(still not sloved)