So, this is my first bug report. Maybe its not even a bug and I just didn't find the option in mIRC.
Anyways, I was happy that mIRC finally had UTF-8 support and worked great until I recently looked into my log file to see many strange characters. I noticed that these characters should be german Umlauts like ö,ä,ü. I guessed this has to be an UTF-8 encoding problem since the weird chars showed up after setting mIRC to "Display and Encode" UTF-8.
So I switched back to "Default" and they were displayed correctly in the log file (also tried switching Font from Verdana to Times New Roman for "better" Unicode support)
These weird chars also appear in the Editbox line after setting Font to "Default" and switching lines with Arrow Up.
I'm not sure if this is a bug, but it would be great to get the chars displayed right in the log file.