I am still having theses issues, in version 18.2. Especially when at lot of text is to be deleted, or when text is to be inserted just after something was deleted.

I am still having issues with getting comments to load. The PDF shows the comments, but Indesign says there is none. I have confirmed in Creative Cloud that my Indesign is up to date.

I am running Indesign 15.0

I did some testing for my Case: Comments to replace Text in Headlines would not be possible if the headline is Transformed to uppercase in the paragraph style.
Text insertions are possible.Maybe this helps.

I can confirm this issue. I've got an 1 page indd file and the corresponding PDF. I can provide the files if needed.
Comments in the headline will not be transferred back to indesign. This is can be easily reproduced.

I'm using ID 14.0.2 on OSX 10.14.5.

Steps to reproduce:
Export Indd to PDF
Comment in Acrobat Reader DC 2019.012.20034
Import Comments in ID

Changes in the Headline will show up as comment, but are not linked to the headline.

I can confirm this issue. I've attached a very simple 1 page indd file and the corresponding PDF. Comments in the headline will not be transferred back to indesign. This is can be easily reproduced.

I'm using ID 14.0.2 on OSX 10.14.5.

Steps to reproduce:
Export Indd to PDF
Comment in Acrobat Reader DC 2019.012.20034
Import Comments in ID

Changes in the Headline will show up as comment, but are not linked to the headline.

The markups in the pdf look as if they are put in correctly, you can see them in acrobat, and then when you load it in Indesign they appear in a list but when you click on one, nothing happens, it doesn't go to the edit, you can't see the edit on the page, it doesn't recognise the comments. I have also had it where it only recognises half. The tool isn't really useful if you can't trust it to load everything.

Great potential but lacks proper execution. I tried stike-thru replace text for a price within a catalog but the formatting was changed when change was applied through imported comments. It appears that it will not hold format of mixed sizes and styles(size, kern, . Hope this gets addressed quickly because I could really make good use of this tool across department(Catalog, newspaper, packaging, magazine, etc)

Hi Uwe -- Yes, it's an InDesign table. So many many problems with the Import PDF Comments feature. Not sure for whom it is useful at this stage. For my work it's terrifyingly destructive. I won't touch it with a 10-foot pole until it's better thought out and implemented.

Hi C W,
is your screenshot showing a table done with the table feature of InDesign?
I found various bugs with comments made to text in table cells.

Regards,
Uwe Laubender
( ACP )

and…

If in PDF text corrections to graphics (eps, ai, pdf) are marked with the PDF correction function, they will not be displayed completly when importing to InDesign. Or these are displayed in the wrong position.

I've tested importing comments (ID 14.0.1 x64 PC) and it's full of bugs.

I've reported this in this thread: https://forums.adobe.com/thread/2565225

Some comments are not shown at the right place in InDesign and if I "accept" them, the change is made at the wrong place.
Sometimes replacing some characters adds a new paragraph.

With this the whole function is useless because I have to control everything in Acrobat, too.