There was a previous discussion here on the OBi forum about a related issue, of caller ID being lost in calls from GV to CC. There was a lot of finger-pointing by CC saying it was GV's problem.
This delayed/missing call problem may or may not be related to the CID issue; I suspect it is. My area code 845 CC DID briefly had the Anonymous CID issue, which then magically went away. Now, it's really FUBAR, and I also intermittently get the delayed or completely non-functional GV-->CC calls. This week, I am now getting a combination of anonymous CID, correct CID, or somebody else's random CID (!!!)
I now think it's pointless to flip between various CC free DIDs; I suspect they all are impacted by the issue, which is most likely as mentioned earlier, something about the route between GV's CLEC and CC's CLEC. Note that my PAID, local CC DID, which is on a different CLEC, works just fine.
My contact at Google opened a bug report for their engineers on the issues today. It would help encourage them to work on it if y'all would please pile on to either of these two discussion threads, depending on which bug you experience:
Please be nice and add helpful data
The anonymous/wrong CID thread: https://productforums.google.com/d/topic/voice/FOMC_n8pYUM/discussion
The delayed or dead call thread: https://productforums.google.com/d/topic/voice/HFVaCVxiD_w/discussion
What their engineers typically want, is a list of a few (3-5) calls, including the last 4 digits of your GV phone number (to authenticate that you own the account they're looking at and acknowledge that they'll be looking at your data), the date(s) and approximate times of calls that are not working, and the last 4 digits of the CC (or Anveo) DID that is not receiving the calls, receiving them late, or receiving them with anonymous or bogus CIDs.