I have a multiclassed warlock that has taken the Book of Ancient Secrets invocation.  At level 3 the text in the character builder says: "When you find such a spell, you can add it to the book if the spell’s level is equal to or less than half your warlock level (rounded up) and if you can spare the time to transcribe the spell." 

I would take this to mean only first and second level rituals but the character builder allows you to choose rituals up to level 6.  Should it not be limited such as the artificer infusion choices?  Is this a copy/paste of the ritual caster feat which is build off character level not class level?

The builder has problems limiting spells.

This might be resolved in future when the revamps of the tools are done.

Until then, use the Spells search function to find info on spells, then just select the right spell name in the book of ancients feature

Thank you, Falconcry! I will raise this with the team.

Hello again! This issue should now be resolved. If the issue persists on your character, please provide a link to the affected sheet. Thank you!

Thank you for the update Mellie!

The Booked of Ancient Secrets is still bugged: https://www.dndbeyond.com/profile/HammerOfGrapthar/characters/38505067