weird shaky screen problem due to using setinterval and vue.js

it's a bizarre problem the program screen starts shaking resizing slightly it's only happens when screen is shrink slightly
please advise what might be happening here
I have a clock that gets displayed in the lower right-hand corner although I had moved it to the center and it made no difference
I am using the sex State mounted to call the setinterval
function it works great until the screen is modified slightly and then it starts breathing as the right Edge moves to the left and to the right an animated fashion.
right now I'll entertain any possible solution it's weird
 
well I can't show the actualcode. I will try in and create a copy to recreate the problem.
set interval causes update of information that is then displayed
within mustaches. {{ datetimestring}}
it would almost seem like maybe it was due to variable fonts
but but then why is it triggered by resizing with screen eg shrinking the screen or adding a component div or span to screen ?

I will post an example of what I'm talking about when I get a chance