Unable to open an existing file. App terminates

[gandm]

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Getting this error when trying to open a file I edited earlier that had some breakpoints set. other files seem unaffected. V3.4 (340012) iPadOS 16.4.1

The app was terminated due to an Objective-C exception. Details below:

2023-05-02 08:05:48.850030 *** -[__NSArrayM replaceObjectAtIndex:withObject:]: index 15 beyond bounds [0 .. 14]