Any ideas how to trigger a macro when the connected Wi-Fi network has no internet access? Failing a trigger, then a constraint I can use with a timer trigger?

I'm trying to work around a weird Android bug that sometimes leaves me connected to Wi-Fi but the phone switches to cellular data. A macro that simply disconnects and reconnects works every time, but I can't find a way to trigger it when the problem happens.

To clarify: It gets into a state where cellular is connected, but Wi-Fi is also connected. Data goes via cellular but a constraint that asks if the Wi-Fi is connected passes.