TFT BUG with lvl 3 champion upgrade! Please fix asap

I had 2 lvl 2 and both had 3 items. I then created a 3rd Level 2 assuming they would combine to a lvl 3 . Not the case. Instead I had 3 lvl 2 on the field. They did not combine to make a lvl 3.

I am not sure if this is an intended mechanic to have champions with multiple items not combine because of the item limit. If that is the case then why not just combine all the lvl 2's and then throw the extra items that exceed the limit back to you to redistribute. This does not make any sense.

Please provide a valid answer.