Netgear router R7900 - question (not about tablo)

Hello everyone! I have a question about routing traffic and I hope the smart people that belong to this forum might be able to clarify for me.

One of the options I have within the settings of the router is traffic limits (could be named something else, but I am at work right now so I can’t look at the actual name of the setting). It can give you a warning message and change the color of the LED lights of the router and even cut off traffic if a certain limit of traffic is reached.

I have the setting enabled to give me a warning message and change the color of the LED light, but NOT to cut off traffic. I just wanted keep an eye on my ISP’s data cap of 1TB (ATT fiber). With my wife working from home for the past year, our data usage has gone up significantly. The past 2 months, we have reached/surpassed that data cap. Luckily, we haven’t been charged for the overage, yet.

The last 2 times I have received my warning message upon login to the router and the LED has changed color, but an unintended consequence is some apps no longer work (refusing to play video) until I reboot the router. I’ve had trouble with sling tv, hbomax, regular youtube. I am doing a reboot (power on/off) not a factory reset of the router. This has only happened when my warning limit I set is triggered. Our ISPs data cap is reset on the 16th of the month and if I get a warning from my router on the 11th, then I’ll have to reboot the router for the next 5 days.

Why would I have trouble with playing videos from the above services when this event is triggered? I’ll most likely turn the option off within my router if it happens again this upcoming month. It could be some weird router bug. Or could it be that my ISP is actually throttling our internet usage? I doubt that because a reboot of the router fixes the situation. Or could it be my wife’s work traffic (through a VPN) causing the issue. Maybe, but none of her traffic is affected when the event is triggered.

I know I could ask other places on the net, but I value this forum’s opinion/expertise. I just wanted to hear your thoughts about this situation.

My internet setup has been like this since I’ve had internet (15+ years), even went through an upgrade from DSL to Fiber a couple years ago. ATT Fiber internet gateway (passthrough mode/DMZ mode)–> netgear router → home devices

Thanks everyone for your attention. I’ll probably just end up turning off that setting, eventually.