If it's really a reverse proxy / Varnish / CDN / etc. misconfiguration issue like some others here suspect, then it could be totally random. The data of some un

If it's really a reverse proxy / Varnish / CDN / etc. misconfiguration issue like some others here suspect, then it could be totally random. The data of some unlucky person whos data happens to get requested when the cache times out will be cached and then sent to all others.