Facebook ads - What counts as a 'post engagement'?

I've only used fb ads a few times before and I cannot seem to find this information anywhere. I'm just doing low bid experiments at the moment, but anyways, what exactly counts as a 'post engagement'? The reason for me asking is because I naively assumed that this would mean actual engagement with the post, but it says I have 8 post engagements but there are no likes or comments, etc. Does this mean that these people clicked through to my page or something?

Would appreciate some insight, because it seems I have no idea what I am doing, lol.

Welp, apparently I thought I was running fb ads, but zuckerbot was sending them to instagram.
Fixed now. lmao.

Every click, every interaction with your post is considered post engagement. Even clicking the read more if you put more text into your post, it is considered an engagement.

naemilion said:

Every click, every interaction with your post is considered post engagement. Even clicking the read more if you put more text into your post, it is considered an engagement.

Click to expand...

I see. That's good to know that even clicking read more counts.
Thanks for the information.