Hi,
I've been in contact with CRM support, and this issue will be fixed in an upcoming release. When this release is due, I don't know.
I did manage to find a workaround using a custom workflow activity. This activity receives the URL as it is generated by CRM and rewrites it in the following way:
<SERVERNAME>/main.aspx?etc=<ENTITY TYPE CODE>&id=<ID OF THE ENTITY>&pagetype=entityrecord&histKey=<RANDOM NUMBER>&newWindow=true
It then returns the rewrited URL.
With kind regards,
Maarten van Sambeek