SEXYZ infinite (?) loop on receive

Synchronet External X/Y/Zmodem  v1.75-Win32  Copyright 2006 Rob Swindell

Reading s:\sbbs\exec\sexyz.ini
Output buffer size: 16384
WinSock 2.0 Running
Waiting for Zmodem sender...
!Received frame: ZRQINIT, expected ZFILE or ZFIN
!Received frame: ZRQINIT, expected ZFILE or ZFIN
!Received frame: ZRQINIT, expected ZFILE or ZFIN
File size: 2457 bytes
Receiving s:\sbbs\node1\temp\VERT.rep (2 KB) via Zmodem

consuming 50% cpu

and fails to abort locally:

-> Aborted Locally (signal: 0)
-> Aborted Locally (signal: 1)