OpenXML Filter: DrawingML text line break repositioning on merge causes some documents to become corrupted

When the filter parameter bPreferenceAddLineSeparatorAsCharacter.b=true and there is a a:p>a:br in a document, it is written back as a:p>a:r>a:br. This causes the repairing dialogue to appear if additional formatting is applied to text before or after a:br.

For instance, if there is a PPTX document with the following UI:

it can be represented after round-tripping as:

Here are the slide parts differences:

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Furthermore, as it was noted, if extra formatting is involved, merged documents can’t be opened correctly by PowerPoint.

For more information please refer to the attached documents.