Booming blade cantrip is not showing up in the character builder

I'm building a Fighter 2/Bard 4, and in the spells section (of the bard) 'Booming Blade' does not show up as a cantrip.

AFAIK it should be in Tasha's (which I own). Any ideas what is going on?

Thank you for clarifying this.

I 'fixed it' by choosing Acolyte under Background.

You may be right that Acolyte should not do it, but both Acolyte and Sage gives access to the Booming Blade cantrip (Magic initiate).

Yes, that totally makes sense.

Either my character is somehow bugged, or there's something else at play in my case. I have the Acolyte background selected and under Bard -> Spells I have Booming Blade available.

Thanks for also providing other ways to get Booming Blade.