Reference screen in Comparison View not updating, showing black

Hello. I am trying to colour match clips and am having a couple of issues with the Reference screen in Comparison View. I am using Premiere Pro CC 2019 on Windows.

1. I have made changes to the sequence, but when I click Comparison View, the reference screen shows clips from an old sequence. I've tried turning on and off Comparison View and I closed Premiere and reopened it a couple of times to see if Reference screen will refresh with the current sequence of clips, and it does not. It keeps showing me the same old clip from an old sequence which I cannot use to colour match.

2. Except for that unusable clip, the rest of the Reference screen just displays black as I scrub through the rest of the clips. The Reference screen is not displaying any of the other clips in my timeline. 

3. Plus, before I started having these aforementioned issues, the Reference screen only allowed me to see about 1 minute, 22 seconds of clips in my over six-minute-long sequence. I need to colour match clips past the 1:22 mark of the sequence, of course, so I'm wondering why it is doing this.

Thank you to anybody who can help me resolve these issues.