No doubt
The issue you're talking about is, in a way, the opposite of the improvement that I was talking about; but it is just as legit.
In the first place, those issues are down to the pass defense. In the second, those issues are, as you say, NOT showing improvement.
The issue with them from my perspective is that I try to use stats to show trends, and in this case the stats are a result of different things, but one of them is definitely late-game collapses.
Here are the numbers:
View attachment 97072
Where DPE=Defensive Pass Efficiency
As you can see, the numbers show a defense that is among the best in the nation for the first 3 quarters in DPE.
Then they play the 4th quarter.
As I mentioned, there are two reasons for this.
One big contributor is opponents slinging the ball all over the yard against backups while they try to cut into a huge lead. That is absolutely part of this. But the other part of this is the same thing your eyes are telling you: Late game collapses.
Without taking the time to break things down play-by-play (in past years, I might have actually done that), all I can tell you is that this is the same team that blew a 20 point lead in Austin and almost blew a 12 point lead in Bloomington. There is no sign that whatever is causing the late game collapses is changing.