25.7.8 update, lost internet access (TCP rejected) on specific devices only ??

[MarieSophieSG]

Hello,
1.LAN RJ45 => 2 laptops
2.WAN
3.LAN RJ45 => bridge to cisco WiFi router (mostly Android devices)
4.LAN RJ45 => not tested.

Running 25.7.7, everything was good. (FW default allow all parameters)
28-Nov, Updating to 25.7.8 => 2 devices lost their Internet access (1 laptop on 1.LAN (RJ45) and 1 laptop on 3.LAN (RJ45)), while the others (Android) kept theirs.
No setup, no parameter changed during/after (compared to before, on 25.7.7)

Checking FW live view, I see these 2 laptops/IP have all TCP cnxion rejected
Since all Androids where still accessing Internet, I swap laptop1 from RJ45 on 1.LAN to WiFi on 3.LAN, same blockage; I switched laptop.2 from RJ45 on 3.LAN to WiFI on 3.LAN, same blcokage.

- How come TCP are now rejected, while everything is the same, same MAC, same static mapping IP, same rules, ...
- What should I do now ? (I tend to break things, so I prefer asking before messing around in the FW rules)

Thank you !
MSSG

[MarieSophieSG]

I've ticked the option to disable FW, but that didn't change any, these devices are still not able to access internet, while the others are unmoved, browsing as usual.
What's very frustrating is that some are on the same LAN, 3 (Android) are accessing the internet, 1 (laptop) is not.
And the more frustration, the less I'm able to think.
And as I know myself, if I start "trying" around, I'm going to break my OPN for sure :(

I really need your light here, suggesting debug path and steps .. 

[Patrick M. Hausen]

If you disable the firewall you also disable NAT, which with common consumer setups with a single possibly dynamic external IPv4 address also breaks all IPv4 Internet connectivity.

Please add some more detail. Are these three internal interfaces (1, 3, 4) configured as separate IP networks or are they joined in a bridge as a single LAN like common consumer routers?

What is the IP address of the laptop that cannot access the Internet? What is its default gateway, what is its DNS server? You can check on the laptop itself.

Kind regards,
Patrick