RAX40 cutting my upload speed?

Hello,

I purchased a RAX40 a few weeks ago. The first few days, my upload speeds were what I was expecting (~30Mbps), but soon after that, I noticed that my upload speeds have been cut in half (now about 13-15Mbps).

I plugged my PC directly into my modem, and I get full speed back (30Mbps), but no matter whether I am directly connected to the router via ethernet or wirelessly via WiFi, my upload speed goes back down to around 13-15Mbps.

Also, all other devices on my network (another PC connected via ethernet plus an iPhone & iPad connected via WiFi) all suffer from the same slower upload speed. Download speed is not affected.

I am on the most recent firmware. I updated to the most recent firmware as soon as I installed the new router, and like I said, for the first few days, my upload speeds were normal (about ~30Mbps).

Does anyone have any ideas what might have caused this? I just tried re-installing the latest firmware, but that didn't fix the issue. Should I revert to an older firmware and see if that helps? Or maybe do a factory reset?

Has anyone else experienced such a thing?

Thanks for your help.