When I try to add the two free rituals from the Ritualist feat while I'm at the spells know capacity the web page crashes and gives the following report:

TypeError: Cannot read property 'type' of undefined at ae (https://www.dndbeyond.com/Content/1-0-379-0/React/CharacterTools/dist/characterBuilder.bundle.min.js:1:193427) at Object.De [as isActive] (https://www.dndbeyond.com/Content/1-0-379-0/React/CharacterTools/dist/characterBuilder.bundle.min.js:1:199193) at t.value (https://www.dndbeyond.com/Content/1-0-379-0/React/CharacterTools/dist/characterBuilder.bundle.min.js:6:129525) at f (https://www.dndbeyond.com/Content/1-0-379-0/React/CharacterTools/dist/characterBuilder.bundle.min.js:25:33621) at beginWork (https://www.dndbeyond.com/Content/1-0-379-0/React/CharacterTools/dist/characterBuilder.bundle.min.js:25:37062) at o (https://www.dndbeyond.com/Content/1-0-379-0/React/CharacterTools/dist/characterBuilder.bundle.min.js:25:53322) at i (https://www.dndbeyond.com/Content/1-0-379-0/React/CharacterTools/dist/characterBuilder.bundle.min.js:25:53595) at b (https://www.dndbeyond.com/Content/1-0-379-0/React/CharacterTools/dist/characterBuilder.bundle.min.js:25:56544) at y (https://www.dndbeyond.com/Content/1-0-379-0/React/CharacterTools/dist/characterBuilder.bundle.min.js:25:56084) at v (https://www.dndbeyond.com/Content/1-0-379-0/React/CharacterTools/dist/characterBuilder.bundle.min.js:25:55921)

Same happens when adding rituals for Tome Warlocks with Book of Ancient secrets Invocations.

States that rituals learned this way don't count against spells learned. But I get a crash when trying to add extra rituals above the spell cap.