Google Sitemaps constant re-verification

Why do we constantly have to re-verify sites.

[Bewenched]

I personally check sitemaps every few days and the last time I checked all was well. No changes to the site etc. This morning I log in and it states that the site has NOT been verified. I check my code for the meta tag provided and it is still there.

Why then would google sitemaps state it was not verified and that NO pages of my site are in the index?

[tedster]

One factor here is probably indicated by what Vanessa Fox told us at the end of September:

You're seeing this activity now because last month, we started rechecking verification a little more often than before.

[webmasterworld.com...]

And a second may be the Many Strange Reports in Google Webmaster Tools [webmasterworld.com] that are being seen recently.

[SEOcritique]

Or you may have a custom 404 page that is giving a 200 response.

[photopassjapan]

Uh... yeah, same here, today it asks us to verify the site again.
Although that word "again" is something i miss from this message, to make it clear this isn't a glitch like the "oh, we don't have anything on your site" was ( for in fact they did, I checked back half a day later and all was well ).

So a "verify the site again" would sound less frightening.

This is probably some time limit to check on your authority as the admin, right? I haven't seen any other checks that'd let them know whether the site is still the same, has the same webmaster / owner... Hmm... yeah, coming to think of it i've always thought they were low on security. Now... i feel much safer ;P

...

Or perhaps it is a glitch.

When did you first verify the site?
Does anyone know of such a time-based re-check?

I'll wait for a few hours, and then verify ours.

[photopassjapan]

Okay... i was a bit quick to jump to conclusions.
In fact our site has a "pending verification".

...

...

You know... when you have started the process, just the server being too busy to check whether it's there.

( It was okay for three months, now it's pending, perhaps there's an automated check scheduled every once in a while, but it postponed because of a busy server? )

...

We'll see.

[photopassjapan]

The system kept on telling us that the site is not verified.
First with yesterday's date, now today's date showed up as the last time checked. ( with the same "system is busy" message... )

I tried to re-verify the site.
Just in case :P

But...

Our system has experienced a temporary problem.

*click [google.com]*

We are experiencing a large number of requests for verification. We'll process your verification request as soon as possible. Check back later for the status of the request.

...which then eventually reverts back to...

The system is currently busy. We will process this verification as soon as possible. Please check back later for an updated status.

[vanessafox]

If the verification file or meta tag still exists on your site when we do our periodic recheck, the site should remain verified. However, we are working on fixing an issue where in a few cases, the site doesn't stay verified after this recheck and instead goes to "pending". It sounds like that may have happened in your case. We should have this fixed very soon.

[photopassjapan]

Yup, today it was fixed...
Now it says verified :)

Thanks!