Reports from numerous sources had indicated that Google would begin the rollout of Android 5.0 to its Nexus devices on November 3. New Android versions are always pushed out to the Nexus family first, and it appeared that Lollipop was going to roll out to the Nexus 7 (2012 and 2013) Wi-Fi, and Nexus 10, before being made available on other Nexus devices later in the month.
But November 3 came and went, and still, no Nexus devices have yet received the over-the-air (OTA) update. It's starting to look like Google made an eleventh hour decision to postpone the OTA updates due to bugs being discovered that could not be resolved in time for the rollout.
Artem Russakovskii from Android Police said that a tipster had revealed that the Lollipop rollout had been "delayed due to some outstanding bugs, now currently scheduled for the 12th".
Phandroid speculates that the key issue that has caused the hold-up is related to a bug that causes excessive battery drain while using Wi-Fi. There are many complaints from Nexus 5 owners in particular about this bug, but other devices have been affected too. Nonetheless, while this issue is real, it remains unclear whether or not it was the main reason behind Google's decision to delay the rollout to November 12.
Meanwhile, Google has said that Android 5.0 will make its way to the Google Nexus 4 and Nexus 5 handsets "in the coming weeks", which more or less falls in line with expectations that these devices would be updated by around the end of November.