This has been the case for several versions.
From the help section in v4.5 on Assemble Edit Recording:
“DV cameras or decks controlled through a 1394 connection and the OHCI protocol do not consistently support the commands for frame-accurate recording. As a result, if you are preparing to record to one of these devices, the insert edit and assemble edit menu choices do not appear in the Digital Cut tool. You can use the Digital Cut tool in either local mode or remote mode, but all tracks are enabled for recording and cannot be modified.”