Hi @Anonymous User
That's weird, i have NowTV Fab Fibre and haven't come across this personally myself using the NowTV Hub Router 2, where like you the majority of my internet activity is downloading with a small amount of uploading.
Can't offer any advice apart from maybe see if factory resetting your Router by holding in the reset button for about 15 seconds helps.
Hopefully more knowledgeable people on here with regards to IT & Networking will offer you some assistance.
Also, i would suggest giving the NowTV Broadband Team a call, where you will find their telephone number under My Account > Orders & Appointments section whilst logged in on here.
When on the Orders & Appointments page click on the green drop down arrow below your live date to reveal the telephone number to call.
Hi @Anonymous User
Hope you get it sorted.
If you can't get through to the Broadband Team via the telephone helpline during your lunch break.
Then you can drop live chat a message from the link below.