Full bench, full field, grabbing unit with brawler gloves and levels up when same unit is on field..

​I grabbed a Twisted Fate level 1 from the carousel that has Brawler's Gloves. My Twisted Fate level 1 on the field already has Thief's Gloves. I have a Twisted Fate level 1 on my bench with no items. My whole entire board and bench is already full. They all combined into a Twisted Fate level 2 on the field however there's only a single Brawler's Glove on the level 2 Twisted Fate and the Thief's Gloves which should've stayed on, has popped off. I can't even attach full items to the twisted fate level 2. I can only attach a single connectable item to the Brawler's Glove and then put more items on. However, I could not attach my Infinity Edge that I just got from killing Kruggs or Seraph's Embrace that I got from the carousel. This must be due to the effect of Thief's Gloves where items can't be placed onto a unit already with Thief's Gloves to prevent exploits and item duping. However, I could not even place any other items on my Twisted Fate other than combining the Brawler's Glove with a random item.