Trim issue

I have come across an odd issue today with the trim command in one of my drawings Using LT 2014. I use the trim command by typing trim in the command prompt and pressing enter twice - I know there are different and possibly easier ways to use the command but this is what I am happy with and have done so for the last 15 years! This usually allows me to trim any line that I click back to the nearest line intersection. However working on a drawing today the trimming back would miss the nearest intersection point with another line (i.e. Trimming would go beyond first intersection point) nd/or leave small sections of the trimmed line. What I find odd that this issue only affects one of my drawings - other drawings don't have the problem.

Any suggestions?

Thanks,

Daryl