Destinypedia is flawed. Especially summaries. You’re reading someone’s opinion. I always try to use direct citations. Just so you can avoid being misled by others headcannon. That disclaimer aside, let’s look at your idea. Namely, the Veil is described in the Cloud Strider lorebook as being a dimensional gateway. The Black Heart for starters, this is a hefty retcon, prior it was an artifact left behind to test us. If humanity could overcome it, then the forces of the Light were not finished off and the Darkness had to come back for it. The Vex do not time travel. They can travel to and from the alternate timelines that branch off of ours. Time in Destiny was explained in Unveiling. Each Universe has one primary timeline, there are an infinite amount of branches that sprout from it and themselves. A infinite web of ‘what-if’s. That’s why they don’t have much of any impact on ours. The Ishtar Collective used the Warmind to trip up the Vex simulation. Believing it too advanced for them to simulate. They mentioned the mind forking back then because that technology was later salvaged post Collapse and became the foundation for the Future War Cult. As that is the device they used to see potential futures. There are only two/three entities traveling back in time. Elsie Bray and the Traveler, which means the Gardner and likely the Winnower. As it’s the Traveler that is sending Elsie back. Seems like they are taking those old threads and reworking them into the current narrative. Wouldn’t think too hard on it. Retcons have to be laid out and explained. The only sleuthing to do is find what things were changed.