Decay rate mystery
Trying again here to get an answer from a Duolingo person:
I have been working over the past few weeks to keep my skill trees trees gold with daily practice, which usually seems to mean 3-5 revision exercises in a language each day. The night before last all my trees were gold apart from the incomplete skills. However last night I opened Duolingo and found that refreshing all decayed skills would involve two French, seven Italian and FIFTEEN German exercises. Has something changed in the mysterious inner workings of the Duolingo algorithms that would have caused this?