ipv6 does not always aquire a prefix

[guysoft]

I am not sure why, but sometimes wlan0 does not get a prefix delegated to it on ipv6. When that happens I get in:

systemctl status dhcpcd.service

returns:

wlan0: no IPv6 Routers available

Sometimes I also get:

Mar 19 22:45:02 hotspot dhcpcd[1108]: wlan0: soliciting a DHCP lease
Mar 19 22:45:03 hotspot dhcpcd[1108]: wlan0: invalid prefix 2a0d:6fc1:2:1f01::/64 + 1/64: Numerical result out of range
Mar 19 22:45:03 hotspot dhcpcd[1108]: wlan0: invalid prefix fdc8:457c:ae1e:1::/64 + 1/64: Numerical result out of range