OPTA TCP problems

I have massive problems using TCP on OPTA. After sending some packets (sometimes only 1) the OPTA stops working. It seems the program is blocking.
An interesting behavior is sending to the PacketSender (https://packetsender.com) it works but not with other applications which my software is written for (professional lighting applications). I'm sending only very small packets (max. 60 bytes).
There is also no way to set the TCP socket to nonblocking (maybe over mbed API?), also the functions Ethernet.setRetransmissionTimeout() and Ethernet.setRetransmissionCount() are not available.
On mbed site I see that there is an issue https://github.com/ARMmbed/mbed-os/issues/15429 for the used microcontroller.

mbedOS Opta v4.0.8
IDE 2.2.1 macOS Sonoma

Start by reviewing the linked mbedOS issue 15429 and the OPTA mbedOS v4.0.8 TCP behavior. Reproduce the block with packets from PacketSender and a professional lighting application, then trace the available socket and Ethernet APIs; done means identifying a confirmed cause and documenting a supported fix or limitation.

Written by the indexing model from the issue text.