I recently noticed that the upload speed of my power line adapter get barely above 1 Mbps, while my upload speed is fine at around 80 Mbps.

The low upload speed is now effecting my use with cloud storage as is now take a really long time to update and upload new files.

When I directly connect to the WiFi or my router, the upload speed is much better at around 20Mbps although as expected my download speed is lower at around 30 Mbps.

I trying to figure out that the reason is for my slow upload speed with my power line adapter, both connect wired with ethernet or with WiFi give my a super upload speed.

I've tried resetting the power line adapter and plugging them into different power sockets, but they give me the same results.

I have also tried the VDSL mode, but does not seem to change anything for me. Same or updating the Firmware or downgrading it to a lower version.

Does anyone have any tips for what I can still try to fix this problem? 

This setup has been working fine for months, but since a week or 2 my upload speed is slow.