I THINK I found it --- Windows 7 Manager does have an option to alter the clock/time format - to append day of the week to the display or add a word in front of the time, etc. It also includes the choice to change the time format. Even if you do not use this option or anything, it appears that it will always change the time to that setting any time you use the program, regardless of the fact that you never touched this tool/option in the program. In addition, it gives you a drop down list to select the time format - you are NOT able to enter your own time format. I want HH:mm ... it has 6 time format choices - the closest to what I want is HH:mm:ss -- so I selected it and the time appears fine now, we'll see if it "randomly changes" again, but I don't think it will .... note that the clock is not displaying the seconds of the HH:mm:ss. So, all is well at the moment then.
I consider this a significant bug in the Yamicsoft program.