I think this study is exploring "persistent" ED, which is less known. ED is a documented side effect, but this shows that some men continue to experience ED even after they stop taking the drug.
The linked Wikipedia article cites references to persistent ED and diminished libido common enough to warrant changing the labeling on the drug in 2014.
So, yes, this study is exploring that side effect, but it's inaccurate to call it "less known".
So, yes, this study is exploring that side effect, but it's inaccurate to call it "less known".
EDIT: fixed some word salad phrasing.