Meta data missing until do cache clean

[utopia]

Hi there

I have a number of websites running different 2.x versions and every so often (sometimes weekly) the sites do not display correctly as the {metadata} tag is returning nothing. At the same time you can login to admin and under Site Admin > Global the metadata field is empty. The metadata exists in the database. You do a cache clean and then everything comes back.

Has anyone else experienced this? Anyone find a solution? Basically it means any production site needs to be closely monitored and is not good at all.

Thanks in advance