Thank you for testing all of this. I just pushed up a commit to fix this, so in the future if you update your scripts that will be included.
What caused this issue?
Most skills have an "item" associated with them. Don't think of it as an actual item in the game, but rather, both items and skills both share a database that can be used to look up info about them. For an actual item, that might be its gold cost or whatever, and for a skill it might be its mana cost.
In this specific instance, the Champion Forge skill does not have an "item" associated with it for additional information. This caused the bot to see it as invalid since every other skill I looked at does have an item to look up. As such, it then skipped the rest of the logic and just returned "empty" for that skill slot.
Was it for all users or just mine?
This is going to sound insane for a second, but stick with me. The answer is "both of those are correct."
The bug affected all users. However, it didn't affect everyone in the same way. Due to the way the bot relies on reading out of process memory, and the way memory allocations can essentially appear "random", plus countless variation due to exactly how you have your client, character, etc. all set up... that leaves some weird scenarios. For you it manifested as the base item address immediately being rejected as invalid, but for another person running the exact same code, their base item address for that skill might have appeared correct and continued on (though, it may have just been reading garbage, random data, which could have other weird consequences).