Hi,
I first ran into this issue last evening, around 12 hours ago.
I noticed that my internet speeds on my Windows 10 computer (connected to powerline adapter through ethernet) were incredibly slow, like 1 Mbps download.
What's worse, Ookla's speedtest also reported that I had 7 full seconds of ping to a location that normally gives me 8 ms.

So today I started troubleshooting. I noticed that the speeds of all my other devices connected to powerline were normal (45-50 Mbps download).
I tried closing all my progams in the backround. I ran a speedtest, speeds were normal.
While I was running another speedtest, I tried starting the TP-PLC Utility (v2.2.3149.12 Build 20180816).
As soon as I opened it, the speeds plummeted. As soon as I closed it, the speeds were up again.

Does anyone know how to fix it? I believe the software was at the same version yesterday, so it probably isn't a bug.
Thanks in advance.