Nano RP2040 - WiFi transmission problem

I am working on an FTP communication, where the RP2040 is the FTP client that send data present on an SD card.

Once the WiFiClient is connected to the FTP server, I send chunk of data.

Really often the WiFiClient.write() function return 0, and often size of data written is not equal to the amount of data passed to the function.

The same code is working perfectly with an ESP32 or an ESP8266.

What type of action could I do to solve this problem?
I've tried different chunk size, without so much difference.

Thanks.

The report names WiFiClient.write() as the failing entry point during FTP transfers from an SD card on the RP2040. Reproduce the short or zero writes and compare them with ESP32 and ESP8266 behavior; done means determining the cause and establishing that the RP2040 sends the requested data reliably.

Written by the indexing model from the issue text.