Rocking a lvl 14 glamour bard and noticed during play that the Beguiling Magic feature seems to not take into account your actual spell save DC. Not sure if this is intentional or not, but with a spell save DC of 20 (shoutout reveler's concertina) mine autofills with a Wisdom 18 save DC. Any idea if this is a bug? Or is it RAW to not count reveler's concertina in this calculation? Thanks for any help/clarification.
Rocking a lvl 14 glamour bard and noticed during play that the Beguiling Magic feature seems to not take into account your actual spell save DC. Not sure if this is intentional or not, but with a spell save DC of 20 (shoutout reveler's concertina) mine autofills with a Wisdom 18 save DC. Any idea if this is a bug? Or is it RAW to not count reveler's concertina in this calculation? Thanks for any help/clarification.

Link to my character sheet for any investigating needing done: https://www.dndbeyond.com/characters/145952292/uFiXMB