Einstein Bot (Enhanced) — "Couldn't build model" despite meeting the 20-utterance requirement

Hi community,

I'm getting a persistent generic error when trying to activate Build Model on an Enhanced Einstein Bot (pt-BR), and I can't pinpoint the cause. 

Setup:

• 61 intents total
• 7 intents with 20 utterances each and mlIntentTrainingEnabled = true
• 54 intents with 3–10 utterances and mlIntentTrainingEnabled = false
• No Intent Sets, Cross-Lingual disabled, all utterances locally defined

One additional note on utterance quality: There are no fully duplicate utterances (identical punctuation and casing), but some phrases appear more than once across intents with case variations only

 (e.g., the same sentence in all-lowercase vs. title case). It's unclear whether the NLP pipeline treats these as duplicates during the build process.  

The issue: Build Model always fails with "Couldn't build model." — no further detail.

Interestingly.  

if I drop any trained intent below 20 utterances, the error 

changes

 to the descriptive validation message listing the affected intent. This confirms the system recognizes my trained intents and their counts — yet the build still fails silently when all requirements appear to be met. 

My suspicion: There may be orphaned MLIntent records in the org — intents previously deployed and later removed from metadata without

 explicit destructive deletion — that are corrupting the ML Domain state without surfacing a clear error. 

Has anyone seen this before? Any way to get more detail beyond the generic UI message?

Thanks!