In Affinity Photo, changes to the Refine Selection Tool Keyboard Shortcuts do not hold between sessions. After restarting the application, the shortcuts for decrease and increase brush size return to default [ and ]. In all of the other tools, changes to the brush size setting remain. I have tried saving and loading to a .affshortcuts file and the changes to these particular settings do not return on load.
This bug is hugely annoying as I use a non-US keyboard layout that does not have these default keys [ ] available on the keyboard without a modifier. In my case using a Swiss-German Keyboard layout, i have to use AltGr+5 or AltGr+6 to get these characters. Naturally, toggling in this way does not work to activate this shortcut in Affinity.