I like the 2K yen notes. They take up less wallet space and are often less used so less dirty. Most I have gotten seemed to be new bills.

The only place I had it questioned was at the Nara Visitor Center years ago by a volunteer who hadn't ever seen one before (?). She went to ask her supervisor and then accepted it without further question, commenting that they are "very rare." I suspect they are like a US $2.00 note, legal tender but rarely seen. Every other time there was never even a doubt.

Short answer - no, no problems with the possible exception of some teen-aged part-timer at a convenience store who has never seen one.