After Update to 7.4.1: error reading status line from remote server localhost:8009

[881822]

Hello,

after updating to v7.4.1 I found error messages in my apache error.log as follows:

(70007)The timeout specified has expired: proxy: error reading status line from remote server localhost:8009
proxy: Error reading from remote server returned by /Microsoft-Server-ActiveSync
(both in the same second)
and later:
File does not exist: /var/www/appsuite/OrderUpd1_files, referer: https://somehost/appsuite/
File does not exist: /var/www/appsuite/apps/io.ox/office, referer: https://somehost/appsuite/

listbundles gives the following output:

/opt/open-xchange/sbin/listbundles|grep -v ACTIVE
bundlename: com.openexchange.system.extension status: RESOLVED
bundlename: slf4j.jcl status: RESOLVED

As far as I know, there is no problem in using OX, but the above mentioned errors fill the logs very intensive.

Any idea