How do I stop transitions from showing media that I've cut from my clips?

I have a million clips that I've previously cut unwanted bits out of, and I have a cross dissolve transition set between each one. My problem is that the transitions are showing parts of the media that I previously cut out. I'd like the transitions to only go over the media that I have visible on my timeline. Is there a simple preference I can change to do this so that I don't have to go back and manually cut the beginnings and ends of each clip?

Transitions need extra material on each end to be created.  Because it makes the clips overlap.  If you know you’re using cross fades, plan for it when you edit.  You can also trim the edit points to adjust when the transitions start and stop. support.apple.com/guide/final-cut-pro/ad...line-vercf3c662c/mac

The quickest thing to do is create, say, a one second freeze frame at the point where you want to transition thus giving more handle to use transition wise. I'll typically speed ramp in these cases instead of freeze frame transitions but if you have lots of them then the most expedient way is freeze frame handles. 

Or just trim them properly as most folks do.

That would make sense but I surmised, correctly I must admit, that this wasn't something he shot or was working with individual clips as no one has ever shot something so exact that the heads and tails were spot on accurate when captured in camera. (Though I have come close to that kind of perfection.)

He's evidently working on an already edited piece and has segmented clips from an edit and as such there isn't anything handle wise for him to work with to keep the head of the trimmed piece from appearing ghost like in the tail of the edit that precedes it. Yep, that's what he's got.

I’ve been in this business for over 20 years now, and I never had issues with trimming for a transition.  Never had to use time-consuming retiming or still frames (which really messes with the visuals badly, very amateur technique).  But, if you work with really bad footage all the time, have a serious talk with your camera crew and director.  But, you’re fairly entitled to your opinion.