The dashboard "All Updates"-list with the 'recently updated pages' will not be updated

the "recently updated"-list stopped to be updated. This is also shown in the dashboard "All Updates"-list.
Only a manually Reindexi updates the list one time. Further edits, or creations after that will not be recognised.
These steps I have already tried without any success.:
1. deleted the index-files; reboot server; manuall reindex
2. deleted plugins cache like described in https://confluence.atlassian.com/display/CONFKB/How+to+clear+Confluence+plugins+cache
3. added the 3 files from patch.zip of https://jira.atlassian.com/browse/CONF-39825
(but did not make changes on the database, because it is on our Oracle-Cluster)
;reboot server; manuall reindex

Please help.

Regards,
Bernhard Wessel