I viewed the console and watched the values… somehow, the calculations were off… after a few minutes, the width reached ridiculous high numbers… in the exponent range. like 3.27343 E3 %
I think the problem with the BS3 version was without the delay(), the browser couldn’t really show the width animation progressing. All you see are just random “snapshots” of the animation. Then on the next loop, it takes those as the initial values (or something like that) and then a percentage applied again, the width just went higher and higher.
If you change the delay numbers and make it lower, you’ll see what I mean. The animation becomes choppy… as if not all the keyframes are being shown. So I had to slow it down with the delay() command.
I have to admit… this was a very unusual problem. We just have to find some workarounds.