I am curious to what they actually added. Using the region/language selector at finnair.com I see no option corresponding to "traditional". The HK selector is iso-code ZH, so it is Cantonese but I am not skilled enough to see how it is scripted. Is it trad or simplified? Canto
can be scripted in simplified to a certain degree, but not all words.
I guess canto speakers in HK would prefer traditional while canto speakers in GuangZhou would "prefer" simplified.
If they added the min nan dialect TW Hokkien (that would be a mess as it didn't appear in writing until ≈200 years ago and uses a mix of characters

I would give the rumor some credit!