Adobe InDesign 2020
15.0.2 x64

Issue:

I am trying to create index entries that include a page range (such as 26-29) instead of a single page number using paragraph styles.

I am having trouble getting the page ranges for my indexed content to update correctly. Specifically, the index entry always only shows the first page of the range in the index pane on the first attempt.

I can sometimes (but not always) trick it into updating the page range correctly. I attached a video of it finally working after five failed attempts.

Here is what I tried:

(Also detailed at: helpx.adobe.com/indesign/using/creating-index.html#pagerangeoptionsinindexes)

Step 1: Select the text that I want to be created as a marker, in this case, "Vacation" (by dragging the selection in the first [failed] video, and triple-clicking in the second video.)

Step 2: Select "Next Use of Style" and use "Heading 2".

Step 3: Click OK.

The first attempt always displays incorrectly.
After toggling between various Page range options, committing each one, and then toggling back to "Next use of Style," I can sometimes get a page range to appear, but it usually incorrect. An example of this behavior is illustrated in the first video when the page range shows 26-67. (It should be 26-29.)

Video two picks up where the first one let off. I try a slew of page range options, consistently returning to "Next use of Style" and "Heading 2" until finally, the correct range appears.

Also, if I need to nest that entry under another, the process starts all over again. :(

UPDATE: It turns out that even the last attempt is a failure. I am posting video #3 to show which pages the styles appear, and in what order. sigh

Links to Videos:

First Attempt: ** (90 seconds)
I did get a page range after much futzing, but not the correct one: https://www.screencast.com/t/dvn4qwpi -or-
***Bug- InDesign Index Page Range Attempt 1.mp4* attached below.

Second Attempt: (2 minutes)
I did get the correct page range after an extreme amount of futzing: https://www.screencast.com/t/KnZRmUQfak -or-
Bug- InDesign Index Page Range Attempt 2.mp4 attached below.

Video 3: (50 seconds)
I use Find Format > Paragraph Style: Heading 2 to show you a small piece of the documents header structure, in case it is at all helpful. The image below (Document with headers labeled pgs 26-30.png) shows this as an annotated image.)
https://www.screencast.com/t/WAksdpdunq -or-
Bug- InDesign Index Page Range Style Information.mp4 attached below.

Images:

I have attached an annotated file that shows the pages and header structure (Document with headers labeled pgs 26-30.png). I also attached a video (Bug- InDesign Index Page Range Style Information.mp4) that shows these are, in fact, the correct styles.

Any help with this would be very much appreciated.