Essentially the issue is that the timers do not show the time for the skills themselves, only for the longest duration effect. If there is another source of the effect the timer duration is removed.

Let's say use mirage and vigor, both give Minor Resolve. If I cast mirage and then vigor I loose the duration of mirage, this also works in reverse.

Here's a video of showing it: https://cdn.discordapp.com/attachments/617081264150806607/1049648253592940544/timer.mp4