UART mode limited to 20 characters about bluefruit_le_connect_v2 HOT 2 OPEN

Confirmed this is an issue. Tested iOS app version 3.7.0 on iOS 17.2.1 with https://github.com/adafruit/Adafruit_CircuitPython_BLE/blob/main/examples/ble_uart_echo_test.py on a Feather nRF52840 running CircuitPython 8.2.9 and also CircuitPython 7.3.3.

from bluefruit_le_connect_v2.

There is no character limit in the app. If the message to be sent is longer than the MTU (Maximum Transfer Unit) negotiated during the BLE connection, the app will slip the text into multiple messages and send them sequentially.

I tested the iOS and macOS versions (3.7.0) and was able to send more than 20 characters.
I used a Bluefruit LE Friend connected to a computer and CoolTerm to check the data received by UART.

So perhaps there could be a problem with the libraries used in CircuitPython?

Adding some more information, 20 bytes was the default MTU for BLE connections for many years. Modern devices usually negotiate a bigger MTU (around 512 bytes) but is not unusual for it to set it to 20 bytes.
So my guess is that the text is split in multiple messages, but the CircuitPython library is only processing the first one (which is 20 bytes long).

from bluefruit_le_connect_v2.