The base64 string decodes to 9 UTF bytes whose hex values are:

	ec b2 9c eb ac b4 ed 98 b8

Not a comma in there.

This UTF string converts to 3 Unicode characters:

	cc9c bb34 d638

This is in the right range for Korean and there isn't a comma
in there at all.

All the =?charset?encoding?stuff?= is supposed to be treated as a
single symbol so you needn't worry about commas in there anyways.

My best guess is that your gui saw some characters that it couldn't
figure out how to display and stuck in its own goofie looking From:
line.