Internet speeds plummeted after the Windows 10 May Update, dropping from 1 Gbps to 100 Mbps

After updating to version 26200.8457 in May, my wired internet speed suddenly slowed down. When I ran a speed test with a Gigabit broadband connection, the download speed dropped to only around 100 Mbps. Everything was working fine with the April version; this issue only appeared after the update. Has anyone else experienced the same problem?