Just updated to ID 2020 15.1 and found a bug which makes the program unusable forcing me to immediately downgrade.
When I open on of my ID documents created in previous version of ID, all of my defined text variables as well as page numbers are corrupted and replaced by the "ss" text. Changing the style has no effect. I can create page number based on the 'Basic Paragraph' style but when i choose any other previously created style, the number changes to 'ss'.
Even the variable field preview shows 'ss' text instead of variable name.
The same document opens in ID 2020 15.0.3 without any problems.

I report a bug regarding an InDesign document of an anomalous character that is found in the "Story editor", which has already been reported in older versions of Adobe Indesign.
(OS version: BigSur 11.3.1)
(Adobe InDesign version: 16.2)

As you can see in the examples that I attach, the text presents problems and I believe it is caused (or highlighted) by the missing glyph signs in each line of the "story editor", which does not appear to exist in the text.

The problem is not solved by making the file idml.
I tried to fix it by copying the text and placing it in a new InDesign file, the result didn't change.
Then I tried to paste the text into "Microsoft Word" and after copying it again I brought it to a new InDesign file and, in that case, the problem disappears (unfortunately, however, I cannot do it with the entire text of the book because it is too complex and I'd basically have to start the job all over again). So I think the bug is only referable to certain files.

I also tried to create a new document by importing all the pages from the old one, but even this operation did not solve the problem.
In addition to this anomaly, I also noticed that clicking in some places of the text (to insert text or delete it manually) the cursor is positioned more and more to the left of where I click (for example, if I click after the last letter of the word after which I want to insert a text, the cursor is positioned between the penultimate and the last letter of that word, it is very annoying on a long job).

The same thing happened to my colleague in the department: another document caused many more problems than mine, especially on a certain page, whatever action he performed, the file often slowed down until the program was closed, it was very difficult for him to complete a job that was now in its final phase.

Finally, as described at the beginning, I point out the links of the posts where this problem has already been reported:

2018:
https://community.adobe.com/t5/indesign/first-character-of-story-editor-and-notes-panel-displays-incorrectly/td-p/9549599/page/2

2020:
https://indesign.uservoice.com/forums/601180-adobe-indesign-bugs

This is getting ridiculous, there are so many bugs in this program it's barely usable anymore. I have a 2 column layout, some content spans to 1 column. Sometimes when there is a table that spans it moves the table to the next page even if there is enough room. The only way to fix this is to make another text box and link them together. This is a huge pain ********** and makes it difficult when there are footnotes. It's a span bug and has been around for a while. Instead of making new features can you fix the tools there are already there.

Hello,

1. Create a new document with 5 pages.


2. Draw out a text frame on each page and insert a number starting with "5" on page 1, "4" on page 2, "3" on page 3, "2" on page 4 and "1" "on page 5.


3. Now try to sort the numbers into the correct order (1, 2, 3, 4, 5) by dragging the thumbnails to the correct place in the Pages palette. You will not succeed because the respective side always jumps one position too far.
   I reported this bug over a year ago and it still isn't fixed! (Indesign version 16.1)