Also note that the threads don't seem to be displaying in proper order unless I log in.

I hope they have fixed a couple of issues I always had with the old forums:-

Yamaha has opened, and closed, the new forum several times since the old one was shut down. There are still unresolved issues that need to be fixed and a lot of cleanup that hasn't been done.

1. the browser differences I mentioned in an earlier reply still exist. You get a different list of recent threads depending on whether you are logged in or not. If you are not logged in you even get a different 'most recent thread' on the 'Forums' tab (one hour ago) and the 'Recent threads' tab (3 weeks ago).

2. the majority of the listings on the 'members' tab show no posts or activity at all even when the join date is several years old. Select the tab and then choose almost any page down several hundred and the entire list of members are like that.

There are some listings that are either SPAM or used for testing. From the members tab search for this member:

'Get Body Masaza To Have Utmost Comfort And Relaxation ' - yes, you read that right. That is the actual member name listed. You will find a lot of others with similar text for the name.

3. the number of members doesn't match - on the main forum page, 'forum information' at the bottom, it shows 35 K Members, but on the Members tab is only shows 2299 pages and only 15 members are listed on each page. Those numbers don't match.

Maybe they haven't migrated all of the users yet or maybe a user has to log in in order for their activity to be migrated.

At least you can now search for old threads. I suggest you find, copy and save anything you are interested in, old or new, in case it disappears if, and when, these things get fixed.

It is great to see progress with these new forums engine.  It's great to be able to post once again, and also to be able to read others new posts.  I use mostly Chrome and sometimes Edge.
I think my experience so far has been much the same as those who also use those browsers.

My preference would be to view "Recent Posts" publicly as the default filter/sort view when not logged on.  I don't always want to be logged onto the forum when viewing & checking out new posts/threads, but as it currently stands I first need to login, even if just for a quick peak at what's new/recent within this 'Montage Series Synthesizers' forum.  Hopefully the current default public filter/sort gets sorted out and will be set to "Recent Posts" eventually (within each of the various Forums).  Perhaps Firefox still has a different experience as Andrew has pointed out..!?

The "Recent Posts" link at the top of each Forum points to https://yamahasynth.com/community/recent/ ; However that takes you out of the forum you are currently in, and sorts for all the various Forums combined; which is not ideal for many who just want to check out recent posts in a specific forum, such as the 'MONTAGE Series Synthesizers' forum, or another specific forum...

Looks like the forum is down again.   The banner currently link resolves to:

https://yamahasynth.com/forum-interruption/

The latest announce still says the forum is open:

https://yamahasynth.com/learn/news/forum-update/

... I'm guessing the interruption is planned on being short.