This was an interesting one! Short version: the issue is now fixed. Read on for details.
The background here is that the new Ibex Farm compresses results on the client side using the 'snappy' algorithm before uploading them to S3. It seems that there was some kind of issue affecting Firefox on Android that caused results compressed using this browser to decode with trailing null bytes. As the issue is browser-specific, only a couple of Jeremy's results were corrupted.
I haven't quite got to the bottom of the underlying issue, but I've done the following:
(i) Added some logic to ignore trailing null bytes when parsing decoded results.
(iii) Blacklisted Firefox on Android from using results compression. (The results will still upload, just in uncompressed form.)