Bug in homebrew subclass spellcasting: 16/3 spells known

Hi. I am trying to create a cleric spellcasting subclass for the Monk. I have encountered a bug.

I started very simply, creating a homebrew subclass for the monk. In the Basic Description, I added text, then added the spell casting features at the bottom:

Then, as I had read in the original subclass changeling, I added one feature called "Spellcasting". It has no options, just text, and the class level selected:

When I go add the subclass to a third level monk, it appear to work. I get the SPELLS tab! Woo! But when I go there, I see a big error exclamation:

So I click in there, and it appears to have pre-selected 16/3 1st level spells (clearly too many, hence the error). Interestingly, cantrips work just fine.

And here's the real bug. When I go to "Remove" spells, it works just fine for the first one (I remove Bane first), but when I go to "Remove" the second one (Bless) it throws an API error. Which is surely a bug. Hence this post.

Now, the API error says to include this data when reporting a bug. I'll try to do that, but the "Payload" text is really long. So long it's crashed my browser a couple of times trying to post it. But I'll try.

Ha ha ha no. There’s so much text in that error that my computer can’t handle it in the copy paste buffer. If you really need it, I can try to get it another way, maybe. The error is 100% reproducible. 

Okay, got it saved to an .rtf file. It's 55.7 MB. Yeah, so let me know if you really need it.

The bug seems to stem from the fact that DDB wont let a subclass be a spell prepare type like the cleric, druid, paladin, or wizard.