Steps to reproduce

Step 1: Play Harmonious Emergence
Step 2: Equip Webspinner Cuff
Step 3: Attack
Step 4: Get blocked by a creature with 6 power
Step 5: Use light the way to make Harmonious Emergence a 6/9 creatures
Step 6: Watch my creature fall apart as the system doesn't register the Webspinner Cuff and returns activates the "sacrifice harmonious emergence" portion.