Does anyone have any idea WHY TradingView keeps changing many candles (and not only the last one) from red to green and vice-versa on Renko Chart?

Here is an example on Poloniex:ETH_BTC H4. They are the same period. Candles were red, then became green, then red again.. It's too weird.

https://imgur.com/SxiYcuK

https://imgur.com/IHJdK1D

Thanks for any help!