New leaves rotten

I adopted this Calathea Medallion from Ikea on January. So far she was thriving, she growed 4 flowers in March and 4 new leaves were growing.
However, only 1 of the new leaves has grown normal, while 2 of them grown yellow and whithered, with the stems flacids and not responding to the pattern of movement of the prayer plant. Ancient leaves are all still good.

I've already removed the leaves; the base of their steams seem to be rotten. I'm considering repotting the plant, as it could be a root problem. If somebody had a previous experience and can give me some advices I would highly appreciate!!

Thanks in advance! #Calathea #Calatheamedalion #medallion