Wireless issue on boot DGN 3500

Hello all,
I have a DGN 3500 router with lede v17.01.2 version and all working fine, during normal operation, but I have as issue on router startup: At boot the wireless start in client mode instead of AP mode (as configured) and I need to stop, start chenge something on configuration and so on (I didn't identified the right procedure), and after some attempts the wireless start in AP mode and all working fine until following router reboot.
This is my wireless configuration:

config wifi-device 'radio0'
option type 'mac80211'
option hwmode '11g'
option path 'pci0000:00/0000:00:0e.0'
option htmode 'HT40'
option channel '8'
option country 'IT'

config wifi-iface 'default_radio0'
option device 'radio0'
option network 'lan'
option key 'xxxxxxxxx'
option ssid 'LEDE'
option mode 'ap'
option encryption 'psk2+tkip+ccmp'

could you help me to understand this issue?
thanks
Ivan