Upon each day, Rithmic is doing the settlement on their positions.
Here you can see an example of position on 6B, where long entry is made on 21st October. Upon each evening (22:25) Rithmic is closing old position with settlement price and opening new position, with settlement price as new position price.
This would lead to the difference in R Trader and TX in two main areas:
-Position Price
-Open PnL