I don't use this much, and this could be a known issue with this resource, but noticed a rather glaring inconsistency today between displayed music and both the midi tune that plays and the lyrics displayed at the bottom of the pane.
The particular hymn I was looking at is "Not What My Hands Have Done" (lyrics: Horatio Bonar). The tune in the graphic is "St.Thomas" (by Aaron Williams). The tune played in the midi is "Leominster" by George William Martin (Harm. Arthur S.Sullivan). The lyrics follow a hymnal I have that uses the Leominster tune.
There is no way to send a typo from the resource in question -- at least not that I could find. But this isn't just a typo, it's a glaring media mismatch.
(If there's another way to report errors like this, please remind me.)