600×90 banner has scroll bars only in Firefox

I’ve inserted 5 banners using js in the middle of my page which is set to 960w.

The banner setting in the js script are 600×90.

They display fine in every browser except Firefox where they have both vertical
and horizontal scroll bars as if they don’t fit. The scroll bars only scroll about
10-20 pixels, and right under those banners is more js that is 800xW and it fits
fine.

Anybody else ever seen something like this? I’ve cleared the cache, restarted Firefox, no change. If I edit the js and make it 620×90, it displays the entire banner – it’s just off center a bit if I do that ??

I’m using WPBakery/Visual Composer – and have noticed some weird stuff going on – tabbed content doesn’t display at all, image carousel isn’t working at all…but those issues are on all browsers whereas this banner issue is only on Firefox.

Thanks!