Okay, I figured this out. I was having the same problem. Despite sorting by name first (change to “List View” in the Project Panel), dragging them over to the timeline still resulted in some of them randomly being out of order. It was driving me crazy because I have 30+ videos and it sucks when you go to join all of them and find ONE or TWO are not in sequence!
I signed up for an account here JUST SO I could update with my findings. Here’s the fix:
Sort your clips in the project panel by name (easier if you change the view type here to “list” view). Make sure the earliest/first clip you want is on top. Now do a CTRL+A to get them all highlighted. Here’s the part that makes the difference – when you go to drag & drop to the timeline, GRAB them by the TOP-MOST clip. That’s it!
So funky and stupid that this makes a difference, but it really does. Hope this pays it forward and helps someone else.