Embedded Videos in Gallery (Stack) resize themselves once you press play, Avenue Template

Site URL: https://www.smreps.com/production-1#/wondros/

Hello. I'm using the Avenue template. I have been adding videos to my various galleries (stacked), linked to different pages across the site. I embed all of them at a dimension of 960x540. Yet while some play in the same size window as the thumbnail, others are reducing down in size once you press play, even though the dimensions are identical to another video above or below it, which don't seem to have a problem. The inconsistency doesn't make sense. As I said, I'm embedding them all with the same dimensions. I'm making sure that native resolution of the video is at least 960x540 from Wiredrive (our industry standard online video vault cloud service). Wiredrive has a build in embed code generator where I can adjust the embed dimensions to a lower resolution if needed. So, for example, even if a video is 1920x1080 on Wiredrive, the embed code generator has a functionality built in where I can reduce it to 960x540, but not vice-versa. Below is an example of an embed code generated by Wiredrive, specifically one that is giving me a problem. This video is 960x540 native in Wiredrive. I will also contact Wiredrive to see what they say about it. But I am curious if the resize is due to the native video being 1920x1080, and the code simply isn't working the way it should once placed into Squarespace. The videos Ive reduced from 1920x1080 to 960x540 in the embed code don't seem to resize in the webpage, while the native 960x540 with no reduction DO resize. Thanks for any insight. 

<iframe src="https://wondros.wiredrive.com/?routekey=iframe-embed&token=60a1836c7ef23fa1a698349ffdc11149&autoplay=0&loop=0&controls=1&color=4EB7D4" width="960" height="540" frameborder="0" webkitAllowFullScreen mozallowfullscreen allowFullScreen allowtransparency></iframe>