I noticed it sunday and it happened again today.
After swapping channel for Thunderwings field boss I was unable to write anything in chat until I ported back to Vern Castle.
After clearing a Guardian Raid I was once again unable to interact with UI elements and not able to buy potions from the potion vendor UI, right click didn’t work, shift+right click didn’t work either.
I used right click in town and the expected “cannot use skills in cities” message popped up confirming the input worked on my end and outside of the vendor UI.
After using a triport to travel within Vern Castle I wasn’t able to buy potions either. I had to travel to another map, here: South Vern, Bellion Ruins to be able to buy potions again.
Thank you for writing up this report!
I’ll get it over to the devs for further review, and thank you for pinpointing when this issue started for you!