Hmm... "uaireadóir" is the form of the word here, but "ruairedóir" is the way it was listed at the start of the lesson. Normally I can work out eclipsing, or lentiting to sort out the 'base' word, but I have no idea what is happening with that bonus 'r'!
That is very strange. It is not shown in the Incubator that way and I checked my own Irish tree and didn't see this. If you spot this again, please share a screenshot! This is definitely a weird mistake.