I think I broke my German tree.
8 days ago I grinded really hard, like really hard on German to finish, I did like 3000 XP in a week. Crazy amount, to say the least.
NOTHING NOTHING has decayed. It's hilarious!! Is that supposed to happen at level 25?
It's not about level 25. It's about having substantially increased your word strength. I used to routinely have essentially nothing degild for months. I just practiced more anyway if I needed it. There's nothing weird about 3000 XP in a week. People sustain levels close to that for months or years on end. Granted, they are probably not a great percentage of users.
If you've done all of those skills very recently, it's quite possible that none of them will have decayed yet, particularly if when you did the lessons you answered the questions quickly and got most of them right. You might very well find that one day in the next couple of weeks suddenly loads of them de-gild all at once.
Have you already installed the recently V0.2 updated "Skill strength viewer" script which works on the new portal - with source language English?
I saw that quite often that the skill strength were not so good but the skill was still gold.
So the best is IMHO to manually strengthen those skills, you see give a poor strength % rating.
I found another bug report thread about manual strengthening various skills on the new portal Scala code: https://www.duolingo.com/comment/22496670/Bug-Report-Some-Skills-are-not-strengthening-from-the-re-written-website
Maybe they fixed it...I will see when I am back strengthening my own - individual - skills (manually).
On Memrise you would have already been beaten by the sheer amount of review words in your backlog because of 4/5h, 12h,..6 days. shorter-time review SR intervals of new learned/planted words :-)
How shall you ever retain your new learned DuoLingo vocabulary when you never have to review it in-time (including shorter time intervals)?