Toys R Us is also showing a "spend $40+, get $20 off" deal on Skylanders (excludes starter packs).
This must be the mysterious $20 discount I got on two transactions tonight. Interestingly, I didn't spend $40 on Skylanders, but on a mix of toys-to-life. My first transaction had a mix of Skylanders ($15 worth), amiibo, and Disney Infinity, and the second had Skylanders ($22 worth) and amiibo. After the discount kicked in, the 'buy $35 of toys-to-life, get $10 off' deal kicked in on the order that was still above $35. What I ended up getting was:
Camo, series 1 Skylander
Dash, Disney Infinity figure (was also on sale for half off)
Dragon's Peak Skylanders Adventure Pack
Pink Yarn Yoshi amiibo
Animal Crossing amiibo 3 pack
Ghost Roaster, Eon's Elite Skylander
Maybe it mistakenly triggers if you hit the $40 mark and have a Skylander in your transaction?