Router update -> printer won't connect

[Tahidi]

So my ISP rolled out an update to my router/modem and gave very ambiguous patch notes. After the update my printer (Canon I-Sensys 633cdw) was no longer able to connect to the router or my other AP. Later on I noticed that it can connect, but it takes 30 to 60 minutes, which isn't very practical.

 

Things I've tried so far

• Used WPS to connect, did not work
• Created a completely new network with an old router, connected without problem.
• Created a quest wifi (has access to internet, but not intranet) with my secondary Asus AP, connected without a problem.
• Reset network settings on my printer, so it can find a new IP and other settings, did not work.
• Forced a free IP to the printer, did not work.

 

So it's safe to say that a setting or a feature on the updated modem is causing this, but because the patch notes are as good as nothing, I can't figure out what is causing this.

 

Full patch notes:

 

• Fixed 2.4Ghz WiFi connectivity

• Fix to Ipv6

• UI improvements

• Added Extender feature

• DYNDNS/DDNS fixes

Bellow you can see how I want the printer to connect (and how it was connected)