This is a bug that I see a lot when adding links but it doesn't always seem to happen. Today, following some experimentation, I think I know now precisely when it happens. Take a look at
You will see one line "Lake Eacham rainbowfish are found in Queensland." in the middle of a lot of "boring" stuff. The boring stuff is long enough to ensure that the sentence is not within the first or last screen when I see the article in Edit (if you have a larger screen, you might want to pad it out some more to achieve the same effect).
If I go to the sentence and add a link to Lake Eacham rainbowfish, the VE suggest only one article and adding that article as the link succeeds (everything works normally). If I go to the sentence and add a link to Queensland, the VE suggests many articles this time, so many they are longer than my screen and there's a scroll bar there. This all seems OK but if you look at the screen beyond the Link dialog box, you will see only "boring" bits. The sentence you were working on appears not to be there. This seems to be when the bugs happens. Anyhow, you choose a link and click Done and the Link dialogue box disappears and you are now positioned in the middle of the boring stuff with the sentence you were working on now off-screen (it's usually a few lines above the top of the screen). When you are adding a number of links to a paragraph, this constant need to go searching for your lost paragraph is very annoying.
If I remove the "boring" stuff at the top (the sentence is now near the start of the article), everything seems to work as it should. If I remove the "boring" stuff at the bottom (the entence is now near the bottom of the article), everything seems to work OK.
It seems to occur only when there is a long list of Link suggestions AND the paragraph being worked on isn't within the first or last screen of the article.