Fellow Skritterians,

something weird is going on this morning!
After ages, I decided to finally start studying tones. For this reason, I activated it in the iOS settings, and also set my HSK1 list to "add" instead of "review" mode.
Added 20 and another 20 (because I use manual add).
So far everything fine.
But on my progress screen, after reviewing all the new items, it says:

Character Writings: Added -18
Definitions: Added -1
Word Writings: Added -11

How can the number of ADDED (not learned) items become negative? Did I actually lose some words now? Is there something wrong with the calculation?

Maybe one more info: For the tones themselves, it says added 3 character tones and 4 word tones... it's like if the added tones are shown as negative numbers in the OTHER study modes.

Try a recalculation of your stats. Go to progress page and click the "Totals" button. This is probably just a calculation issue.

Yes, maybe... I tried what you suggested and still same result.

Not sure what happened, but I wouldn't be surprised if there were some progress oddities from early versions of the iOS app.

The progress recalculator can leave you with discontinuities in the relative numbers, but should leave the absolute numbers as correct starting from now onward, so you'd be good to go starting from when you used it. It'll just look weird when you look at the transition day.