unfortunately, the sad truth about dslreports, who for years has remained an unbiased provider of a truly accurate speedtest, is that their test no longer functions appropriately in modern browsers.

however, due to this, https://www.waveform.com/tools/bufferbloat was born. they mention this along with their specific reasons in the FAQ on the linked page.

so, update your bookmarks and plan to continue spreading the good word with this new provider in place.