Scheduled operations scheduled at the same time

Can someone elaborate on how and why this kind of scheduling happens?

Different operations, different products, same resource group. Why does scheduling allow suggestions to appear in the middle of a locked and scheduled work order?

Are you scheduling infinite?

FInite window 360 days. Calendars setup, resources correctly. In most cases it shows correct cascade scheduling, but this one does not. I cannot find why is this different. I mean the suggestion could be done before or after this, but this is overlapping. There is plenty of capacity, but not for this.

I am assuming SUG are unfirm job suggestions. If you firm one does it still try to schedule it where it is suggested?

Well, no, that is not it. I think it is an operational setting. Seems that even different operations can overlap when they do not have finish-to-start on. This for me is illogical a bit because the resource is booked for one operation and then another one is running at the same machine at the same time. Suggestions themselves do look nice:

Another example of which I do not understand the reason for. Same product, but scheduling is making it OK and NOK:

I have gone over all settings and parameters that I could think of and find, but these appear still.