This likely isn't strictly a bug, but you can create multiple jump points on any body capable of sustaining jump points. I do not know if there's a max limit or if there's any downsides to doing so (it has not generated any errors so far as I have seen, and you can use these jump points as normal). When initially created it will appear (at least visually) another 60 degrees behind the L5 Lagrange point until you pass time and then it will show up at the L5 Lagrange point, overlaying any other jump points there. link to image:
https://photos. app. goo. gl/xm5k3F1jgYdrQtMa7
In case this is relevant, this was a Conventional Start and it has been 44 years since the start, I am using real stars (I believe), decimal separator (US computer), I have not tried it in other games yet, but seems easily recreatable in this current game as every body in the Sol system currently has 3 jump points (I was expecting that since I could create more than one that the other jump points would show up in the other lagrange points, such as the L4, and wasn't certain if them overlapping was a visual bug, a mechanic bug in causing them to take the same position, or a minor bug of allowing the creation of multiple jump points when 1 is sufficient).
Also not certain if anyone else has ever posted about this before (I have not checked the entire bug thread to see), so apologies if you are already aware and haven't fixed it as it is relatively unimportant as it doesn't seem to cause any weird behavior besides being mildly confusing to me.