Problem Description:
Querying navigation points inside a movie trigger errors from InDesign 16.

Steps to Reproduce:
1. Query movie.navigationPoints.length or movie.navigationPoints.count() with Extendscript.

The following script shows this issue(s) with simple document containing a move and one button with a play at navigation point action applied.

var btn = app.activeDocument.buttons[0];
var beh = btn.behaviors[0];
var mov = beh.movieItem;
var navPts = mov.navigationPoints;
try{

alert(navPts.length); /*doesn't exist*/

}catch(err) { alert([err,err.line])}

try{

alert(navPts.count()); /*Give incorrect error - Error: Request failed because the underlying functionality is no longer available in the current version of the application */

}catch(err) { alert([err,err.line])}

alert(navPts.everyItem().getElements().length); /incorrectly says zero, when there are 2 navigation points/

Actual Result:
Each produces two separate errors.

Expected Result::
Both should be valid queries.

Any Workarounds:

No. Expected functionality is simply missing.

movie.navigationPoints.everyItem().getElements().length at least doesn't produce an error, but it also doesn't include navigation points.

This feature was added back to InDesign, but the scripting of it was neglected. I've filed a bug in prerelease as well. Posting here so others are aware.

Enter only "^" in the GREP search string field and click the search button to select the insertion point at the beginning of the paragraph. But this cannot be used for replacement. The replacement result is 0.
I gave up that it was only useful for simple pointing tricks, but when I run it from a script the application hangs.

It is like this. (When executed, the rainbow cursor will rotate forever.
Please be careful. )

app.findGrepPreferences.findWhat = "^";
var res = app.activeDocument.findGrep ();

If the replacement string field is "~ c" (the contents of the clipboard), the first character is lost from the original text instead of entering it.
This is also a very dangerous behavior.

Requests for improvement include:
Improved to prevent hang when executing the above script,
If possible, replace text (add a character string to the beginning of a paragraph).

GREP検索文字列の欄に"^"だけを入力、検索ボタンをクリックすると、段落の先頭の挿入点が選択されます。しかしこれを置換には利用できません。置換結果は0個となります。
単なるポインティングの小技にしか役に立たないと諦めていましたが、これをスクリプトから実行するとアプリケーションがハングアップします。

こんな具合です。（実行するとレインボーカーソルが永遠に回転します。
ご注意ください。）

app.findGrepPreferences.findWhat = "^";
var res = app.activeDocument.findGrep();

また、置換文字列の欄が"~c"（クリップボードの内容）などの場合、それが入る代わりに元のテキストから先頭の1文字が失われます。
これも非常に危険な挙動であると言えます。

改善の要望としては、
上記のようなスクリプトを実行した際にハングアップしないよう改善、
そして可能であればテキストを置換（段落の先頭に文字列を追加）できるよう改善。

Extensions and scripts halting or crashing after installing CC2020, due to a missing type library.
Our customers report errors after updating to CC2020, and I got the same error when I tried. Our script make a halt at a DoScript call, with this error: 104705: Unable to load Adobe InDesign Type Library (Version 1.0)
After starting InDesign CC2020 "AS ADMINISTRATOR", a missing type library is obviously created: the message and error disappears after doing that once.
It was not enough for my user just to have administrator privileges on my computer and in the domain, I had to explicitly start InDesign as Administrator.
I found the answer here: https://community.adobe.com/t5/indesign/doscript-error-unable-to-load-adobe-indesign-type-library-version-1-0/m-p/11335921?page=1#M197052

This needs to be fixed in the Adobe installation package for CC2020. Otherwise many script end-user will have to call support and have someone to start InDesign as administrator for them (in case they are not allowed to do that themselves) – it's not obvious to an end user what to do at all when this error occurs.

The sequence of letters -xx'-x crashes InDesign 2021 (v 16.0) as soon as you write this sequence yourself, copy or mark a letter from it (e.g. to change the text size) or do a search for this string, in a normal text field.

To reproduce the issue, simply write -xx'-x into a text field in InDesign 2021 or copy it into the text field. The X'x can be replaced here by other normal letters, upper and lower case doesn't seem to matter. The crash seems not to happen if the last X is a special character like ";" or "! Furthermore, there must be two or more letters before the '-x

The Font-Family also doesn´t play a role here. We tested it with different fonts.

Since we have a lot of documents with this letter combination, we cannot edit them in Indesign 2021 anymore. On InDesign 2020 it worked without problems.

Tested with InDesign 2021 (German Version) on different Imacs and Macbooks with macOS Catalina 10.15.6 and Imac with Mojave macOS 10.14.