Incomplete field reference in note returns unclear error

1. What is the issue? Please be detailed.
I had an errant field in a note that was missing the }. This uploaded and validated ok.

In Enketo it displayed as text eg; let ${1st_value} = 'annona', ${2nd_value} = 'bacuri', ${3rd_value}= 'calamansi':

Your first value: annona
Your second value: ${2nd_value
Your third value: calamansi

But in Collect when trying to load the screen containing it (was a standalone note outside of a group) it showed this error and jumped past the screen. The record could be saved as draft, navigation could be used to access other screens, but that screen was inaccessible.
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Loading the draft returns the same error, after 'OK' it shows:
image

From here 'go to start' or 'go to end' can be used to access other parts of the form, but using the navigation view will throw the same error when it tries to show the summary with the bad field.

Is it possible to validate for incomplete ${field_names} if there's a space/carriage return before the } and prevent upload without fixing?

Hi @ahblake,
Would you mind to share an example or extract of the form, for further analysis, please?

pyxform issue to explicitly identify and error on that case: https://github.com/XLSForm/pyxform/issues/724

The really terrible Collect error is because it uses a ${} notation for placeholders in labels and it's trying to substitute in values over and over again.