This is an issue not with SmartSheet but with this forum.
I have tried Chrome, Opera, Firefox and Edge on Windows and Chrome and Firefox on Linux and get exactly the same behaviour:
The issue affects just content in the Comments section of posts in the Community.
When I am not logged in to the Community and open one of my posts I can select any text in the comments section and click on links in the comments section. Notice in the pic below that the mouse pointer changes to a hand over the hyperlink indicating it is clickable and indeed when I click the hyperlink is opened.
However when I log in to the community I can no longer select any text in the comments section. I can select text in the original post, above the comments section (on the same page). But I can't click on any of the links in the comments section either, so I can't click on the Edit hyperlink to edit the post. See in the image below the mouse icon remains as an arrow when I hover over the link and on clicking no action is performed. This the case for all the links in the comments section - I can't click on the Reply link either.
As I mentioned this seems to happen with all browsers. In Chrome I have tried an incognito tab, clearing cookies and cache and rebooting my Windows machine with no change in behaviour.