Plone sends a link to cached but empty ploneCustom.css

I run three Plone sites on a Plone instance using Plone virtual hosting behind Apache with no caching. On one of them, I keep hitting a css caching issue.

The HTML pages are is shipped with a css link tag

<link rel="stylesheet" type="text/css" media="all" href="http://SITE/portal_css/Sunburst%20Theme/ploneCustom-cachekey5756.css" />

Response to a HEAD request:

$ curl --head 'http://SITE/portal_css/Sunburst%20Theme/ploneCustom-cachekey5756.css'
HTTP/1.1 200 OK
Date: Tue, 14 Jun 2011 06:35:49 GMT
Server: Zope/(2.12.13, python 2.6.5, linux2) ZServer/1.1
Content-Length: 2412
Accept-Ranges: bytes
Expires: Tue, 21 Jun 2011 06:35:49 GMT
Last-Modified: Tue, 14 Jun 2011 06:35:49 GMT
Etag: ts08033349.33
Cache-Control: max-age=604800
Content-Type: text/css;charset=utf-8

However, instead of my elaborate开发者_开发问答 custom css that response contains no data:

$ curl 'http://SITE/portal_css/Sunburst%20Theme/ploneCustom-cachekey5756.css'
$

That means the pages are rendered using Plone default style, causing irritations on part of my site users.

Manually re-cooking the css in portal_css -> Save creates a link to a valid ploneCustom.css definition again, for some time.

This keeps occuring on this one site only, the other two are fine.

Why does this happen? How can I fix this?

Thanks, fbmd

http://pypi.python.org/pypi/Products.ResourceRegistries/2.0.4

this could fix it, I've asked if it can installed in plone 4.0.X but got no answer. Follow the ticket #9849 in plone bug tracker: http://dev.plone.org/plone/ticket/9849