We had confirmed reports from webmasters that Bing was no longer showing up in the log files with fake referrers. But I am seeing a new report that the log files are showing Microsoft Bing IP addresses in them but without referrer data.
An updated Bing Forum thread has one webmaster explaining the situation:
Unfortunately, the problem is back in another shape!
I have almost the same number of fake referrer hits from bing but in a different shape: no referrer. So, the stats show me the pages visited, no referrer and the IPs (microsoft's) are like: 22.214.171.124, 126.96.36.199, 188.8.131.52
So this does not generate fake keyword referrer data, but it does spike up Bing's referrer traffic for specific pages. That is assuming the webmaster who posted this is correct.
Forum discussion at Bing Forum.