Resumed download after suspend concatenates entire file with partial file (?)

[anohren]

Steps to reproduce

Not sure if it's reproducible.

1. Started downloading https://downloads.scummvm.org/frs/scummvm/2.8.1/scummvm-2.8.1-win32.exe and https://downloads.scummvm.org/frs/scummvm/2.8.1/scummvm-2.8.1-win32.zip using links on https://scummvm.org/downloads/
2. Let the phone screen lock activate automatically
3. When unlocking phone later (app in foreground) the downloads seemed to pick up where they left off, according to the progress bar toast
4. Ended up with non-runnable exe and non-extractable zip, both significantly larger than expected (198 and 187 MB respectively)

Expected behavior

Resumed download results in non-corrupt files

Actual behavior

Files too large and unusable.

I thought I'd be able to find the exact byte offset where the start of the file repeated through hexdump and grep but there was only one occurrence of the first bytes 4d 5a 50 00.

Then I noticed that those bytes spell out "MZP", and I immediately thought "Mozilla partial...?"

Device & build information

• Device: iPhone 8, iOS 16.7.6
• Build version: Firefox 125.2 (41035)
• First seen version: never seen before

Notes

Attachments:

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