This sort of thing has been asked for previously.
Bottom line, until the first recording is completed successfully, MC can't apply the "do not record programs that have recorded in the past" rule. What if the first recording fails? Perhaps a power failure, or the PC is off, or similar.
If MC doesn't plan to record the later viewings, it can't identify potential tuner availability issues. It doesn't have fuzzy logic to say, "Well, the second recording probably isn't going to be required, so I'll use the last tuner for this other program and hope for the best." If the first recording fails and MC is over-committed for tuners, will you be there to see a popup message asking you to prioritise which programs to record in the later time slots? Or do you set Priority on every one of your Recording Rules? I know I don't. I just mark a few rules as high priority usually, and leave the rest at the default Medium priority.
It's a can of worms really. Best to plan to record all showings, and then skip them once a successful recording is done, as MC does now.
For example, sometimes reruns of 2-hour premier shows up in listings as two 1-hour episodes with the same title and episode number.
That sounds like an EPG data issue, and not a MC issue. How does a two hour episode become two one hours episodes, both of which are the same?
What I see more often is the premier is episodes 1 and 2 shown back to back, and the later episodes 1 and 2 are shown separately in the EPG, but still possibly broadcast back to back. In that case, each separate episode should have different numbering and naming.
Only manual intervention can sort that sort of stuff out. Usually I watch the premier, then let the individual episodes record, fix the metadata which is often wrong in these circumstances, and delete the premier recording. That way I have individual recordings of all episodes, if I want to keep the program for a while.