W5500 Transmit Garbled

Getting garbled data transmitted from a W5500 included on a Mikro Eth Wiz Click shield board, and the WIZnet supplied loopback.c routine to echo received messages. Processor is a Microchip PIC24FJ1024GB610 on an Explorer 16/32 board. Added test fprintf statements show the message was received correctly from TeraTerm Telnet Port 5000. Also fprintf statements show the correct transmit buffer read back after transmission from the same W5500 location as used to transmit. In Wireshark, I see the correct bytes being sent out from TeraTerm, but on receive I see different bytes each time with no pattern I can discern. But it does have the correct number of bytes. The characters are outside the normal printable stuff so various symbols show on TeraTerm.

So would seem the SPI must be OK if I can receive properly and even read back from the transmit buffer. Also the W5500 seems to be configured OK and responds to pings (as well as receiving the correct bytes from TeraTerm). Suggestions on what I can try next?