Would you happen to be running a version of mIRC between 7.33 - 7.41?

There is a bug in those versions that deal with server-time. It was fixed in 7.42

Quote
17/07/2015 - mIRC v7.42
...
26.Added support for IRCv3 message tags. mIRC will now automatically
remove @ prefixed tags from incoming server messages and store
them in the $msgtags identifier. The CAP server-time "time" tag
can now be parsed when mixed with other tags.

Check your version number:


Help -> About mIRC

or

Code
//echo -a $version