I see that you are pretty new to WikiTree, Josephine - so I wish you welcome.
It does not look as if there was anything wrong with the merges you did. One of the profile managers proposed these merges in March, two months ago and then never got around to completing them (which could have been done in the beginning of April).
If you look at the descendant view https://www.wikitree.com/genealogy/Garrett-Descendants-6906 you can see that there are two branches going down from this couple - one of them ending with the second generation (somebody has been researching "top down", the other going down several generations to somebody who has entered a DNA kit number, which then has propagated up the tree.
WikiTree profiles are never created from DNA data, the inclusion of DNA just makes it possible to match up DNA with a paper trail.
WikiTree is at the base about paper trails, so profiles should always have sources for the dates and relationships, firmly establishing the paper trail. I must say that the sources for the Hodd-Garret couple do not look at all sufficient (which is not to say that these sources don't exist somewhere).
Now, if performing merges makes you lose sleep, stay away from them for a while :-) Ther is much else to have fun with at WikiTree.
