As @fefrei said, you are not on beta, so you should expect certain things to break now and then.
The locale files still contain obsolete translations which are causing this glitch.
This will fix itself within the next few days. It needs a complete translation round-trip:
- upload of the current English locale files to Transifex
- optional: give translators a chance to translate the new pluralized strings
- download the translated locale files from Transifex
That’s how it usually works. But in this case the existing translations are wrong and the code responsible for showing those labels can’t handle that.