Forum content dates only appear in the form Month and Date for all. It is not clear how old it is without hover on date. So -at least- for past years, format should contain Year IMO.
I totally agree with you that this is not presented very clearly. However, if you look really closely, I believe that once a post is no longer within the current calendar year, the year supplants the date.
An example: I post something today, which is 30 November 2020. Until the end of December, it’ll appear as “Nov 30”. Once we get into 2021, it will display as “Nov '20”. That tiny apostrophe is the clue.
You are right i see them with year anymore. But is it a new feature? Because a few days ago i came from Google to read a topic. It was showing only day and month. When i hover it i saw it’s 2018. Of course it might be my fault. There is no problem at the moment.
I can’t say for certain. I feel like it’s been that way for years, but I do know that they did change some things recently (like the default font and landing spot for clicking on the logo).