Won this rift battle but my opponent was suspicious enough for me. You might want to investigate. Keep in mind my opponents rarely score over 22k vs my base, even when their collections are stronger than mine. Anyone scoring over 23k using weaker characters automatically raises one of my eyebrows.
The second screenshot shows the most suspicious fight. Top triple node with Scratching Post and gold Final Fight catalysts. Most players fail against that node, and the ones that do not definitely use stronger characters.
Rift started around 14:20 (UTC -3), April 15th, 2020.