Can't reproduce it. If the timer command was so unstable it would have been reported years ago.
Sometimes creating another /timertest will cause the timer to be reset. Originally when you said "early" I thought you meant half a second or so, I was going to suggest using the -h switch for a high res timer. But since you said it's about 40-50 seconds off, I'd have to say this is probably due to programmer error, not mirc.
