When I view content posted by users and my friend, for example when they buy or receive games as a gift, the text box to write comments does not appear, even though their profiles are public or set to friends-only. Meanwhile, for all other types of content such as screenshots, artworks etc I can comment and see the box to write.
The point is that some days ago I managed to comment under some games received by a friend, but only a few hours later, and a few hours after I wrote, the text box disappeared again and I can no longer even see my comment, even though it’s still there because my friend sent me a screenshot and her profile is set to only-friends for all contents. This happens seemingly at random and only regarding the games received or purchased. Sometimes the box is visible, sometimes it’s not. This is a bug many people are experiencing. It only appears under received games, not under other types of content. I’ve also tried from a browser but the problem persists. I even cleared the cache, uninstalled Steam, cleaned the folders and reinstalled, but nothing changed. This bug has been going on for quite some time. My friend tried last week to set her profile to public to see if I could comment, because she has always had it on friends-only. Only in that case did the box to write appear, but this is not normal because I’ve always been able to comment in friends’ feeds even if their profiles are set to friends-only. Moreover, every time I comment on profiles just to say hi or something, I get an error that says (Sorry, some kind of error has occurred: There was an error communicating with the network. Please try again later).
But the comment still gets posted despite the error, although I have to refresh the page every time, and this error shows up every single time I comment on friends’ profiles. I’ve been having this issue for a long time, but not being able to comment in the feed only under received games is quite strange because I’ve always been able to comment, and it’s a problem that happens very often, almost always, and it’s random, especially after the latest updates and It doesn’t work from browser either.

I sent the same report to Valve support who asked me to explain the issue better. What should I explain better than this? I can't comment because the text box doesn't appear, only if the profiles are public. In practice, even Valve hasn't understood anything at all.
By now, with all these useless updates they have introduced a myriad of bugs.
Many times it gives an error even when I put likes on friends contents,

The support asked me to switch to Steam Beta, but the problem persists. They don't even know what to say. Switching to Beta doesn't mean the problems get fixed, since the issue is still clearly there for me.

Valve have a way of working that leaves much to be desired, they update without checking first.