YouTube embeds playing wrong videos
Don't have enough reps to comment - but it does not seem to be a Craft issue - but rather a Bootstrap modal issue. It seems like when you open the video, it updates the id of the video.

Based on past experiences - I would look into destroying the modal instance and reloading new content in one modal, as opposed to having multiple modal for multiple content.

Update: Just looked a little more into your code and how it's reacting - it seems like on modal close (of either modals), it updates the value of the video embed code to the varilift-lx video.

^ Caused by scripts.js - Line 2172 - 2174

$('.modal').on('hidden.bs.modal', function () {
    $('.video-container iframe').attr("src", $(".video-container iframe").attr("src"));
});


It is grabing the first video container and updating it to that value.