I found a bug in the windows 12.1.x agents (other versions I didn't test), because of which the agent aborts as the target of a large filetransfer. The file was about 44G large. When nearly 8G was transferred, the agent aborted and wrote a dump and a crash_...log file with the following exception message:
Exception information, code 0xC0000005 - The thread attempts to read from or write to a virtual address for which it does not have access. Exception address 0x00007FF6AB941458
The support finally gave me a version of the agent that seems to work (the filetransfer is still running, but the file is already larger than 8G). I'll let you know when the bugfix is released.