The Sitemap Generator has been working well for weeks, then I began getting "invalid tag value" warnings from Google when I checked the sitemap there. I upgraded from version 2.5 to 2.6 to see if that would help, but it made no difference.
The invalid tag warnings are due to dates being put in as the value for the "priority" tag and the characters "52/" put in as the value for the "changefreq" tag, but why these are being put in instead of the correct values I have no clue. The affected tags also have the incorrect date inserted for the "lastmod" date.
I have the change frequency set to "monthly" and the default priority set to "0.5" in my configuration. The sitemap is re-generated every night via a cron job, but at the moment, the invalid tag values occur in pairs for the same pages on the following lines:
So the problem isn't consistent; it doesn't affect all the pages, only a few.
You can see the sitemap at:
[external links are visible to admins only]
I tried deleting the sitemap and letting it re-generate, but it didn't solve the problem.
Any idea how I can fix this?