Here's one way I've found to reproduce it:
Load into a map while you're already in a party with a player in the map you're loading into
Leave the party
Create a squad
Try to use a ground-targeted skill
Note: The position of the other player in your party seems to play a role in this. If the other player is too close to you, or too far away (so that you can't click on them), then ground-targeted skills will work fine.
I have recorded a video of these steps: