last-saved file can sometimes result in InvalidStructureException

[lognaturel]

Crashlytics (requires auth), reported happening many times by user on branded fork but only after making ~90 successful submissions

ODK Collect version

v2024.2.1

Android version

12

Device used

Tecno Transsion

Problem description

When users try to open a form with last-saved, they get the following in an error dialog:

Fatal Exception: org.javarosa.xform.parse.XFormParseException
Unable to parse external secondary instance: org.javarosa.xml.util.InvalidStructureException: Invalid XML Structure(END_DOCUMENT null@1:1167 in java.io.InputStreamReader@e3d0d3): Exception while trying to parse an XML Tree, got something other than tags and text Problem found at nodeset: /html/head/model[@xforms-version=1.0.0]/instance With element <instance id="__last-saved" src="jr://instance/last-saved"/> 

The Crashlytics event is from doing a bulk finalize. I wonder whether maybe the one on form open is not logged.

Steps to reproduce the problem

I can reproduce by manually changing the last-saved.xml file and then I can no longer open the form. I have no idea how that file can become corrupt.

Expected behavior

last-saved file does not get corrupt.

Additional information

I suspect it might have something to do with character encoding or special characters.