When pick blocking a lighting rod in creative, you won't be able to place the lightning rod, or drop it from your hotbar. You have to drop the rod from your inventory to get rid of it. Lightning rods from crafting/creative inventory don't have this issue.

How to reproduce
1. Get a lightning rod and place it.
2. Remove all lightning rods from your inventory
3. Pickblock the lightning rod you already placed, and try to place the new one in your inventory.