An inconsistency that I've repeatedly mentioned to previous maintainers:

'ip a' shows that network configuration under ifupdown is different for Ethernet and WiFi interfaces. Ethernet interfaces get a LL6 address whereas WiFi interfaces don't.

Martin-Éric
--- /etc/network/interfaces.d/*:
##########/etc/network/interfaces.d/funkyware_hostapd ##########
iface wlp0s29u1u1 inet manual
	hostapd /etc/hostapd/wlp0s29u1u1.conf
iface wlp0s29u1u3 inet manual
	hostapd /etc/hostapd/wlp0s29u1u3.conf
##########/etc/network/interfaces.d/funkyware_hostapd ##########

--- up and down scripts installed:
/etc/network/if-down.d:
total 8
lrwxrwxrwx 1 root root   33 Mar 11  2025 bridge -> /usr/lib/bridge-utils/ifupdown.sh
-rwxr-xr-x 1 root root 1677 Feb 18  2023 clamav-freshclam-ifupdown
-rwxr-xr-x 1 root root  759 Dec  9  2022 resolved
lrwxrwxrwx 1 root root   32 Mar 22  2025 wpasupplicant -> ../../wpa_supplicant/ifupdown.sh

/etc/network/if-post-down.d:
total 0
lrwxrwxrwx 1 root root 33 Mar 11  2025 bridge -> /usr/lib/bridge-utils/ifupdown.sh
lrwxrwxrwx 1 root root 25 Mar 22  2025 hostapd -> ../../hostapd/ifupdown.sh
lrwxrwxrwx 1 root root 32 Mar 22  2025 wpasupplicant -> ../../wpa_supplicant/ifupdown.sh

/etc/network/if-pre-up.d:
total 4
lrwxrwxrwx 1 root root  33 Mar 11  2025 bridge -> /usr/lib/bridge-utils/ifupdown.sh
-rwxr-xr-x 1 root root 348 Jun 26 21:30 ethtool
lrwxrwxrwx 1 root root  25 Mar 22  2025 hostapd -> ../../hostapd/ifupdown.sh
lrwxrwxrwx 1 root root  32 Mar 22  2025 wpasupplicant -> ../../wpa_supplicant/ifupdown.sh

/etc/network/if-up.d:
total 16
-rwxr-xr-x 1 root root 1677 Feb 18  2023 clamav-freshclam-ifupdown
-rwxr-xr-x 1 root root 1689 Jun 26 21:30 ethtool
-rwxr-xr-x 1 root root 4665 Aug 20  2024 resolved
lrwxrwxrwx 1 root root   32 Mar 22  2025 wpasupplicant -> ../../wpa_supplicant/ifupdown.sh

Hi Martin,

Seems to me this is a duplicate of #1036657 in bridge-utils.

I don't see missing link-locals in my plain wifi setup, can you reproduce
this without involving any bridging?