[Zope] Strange behaviour - 3 links which should be the same don't

[Sasha Vincic]

Hi,

Following 3 URLs should return the same content but they don't, why?

Link 1 (works)
http://reports.eea.eu.int/briefing_2005_3/da

Link 2 & 3 (content borked)
http://reports.eea.eu.int/briefing_2005_3/da/
http://reports.eea.eu.int/briefing_2005_3/da/index_html

Enviroment: Zope 2.7.3 upgraded from 2.6.4
The objects in the url are from ZClasses and index_html is a DTML
Method. If I do abstract.decode() the links would work, but since this
is a very OLD site and one of the links works I would like to know why
before I start changing couple years old templates.

Title and Abstract text are UTF8 encoded in a textfield. ZMI form is
UTF8 encoded and looks good when you edit it.