If you set both channels of the protocol decoders to 8 data bits, odd parity, 1 stop then the errors go away (8O1), but I don't know about the data.

Are you sure about the format? You don't include the parity bit in the count of data bits. Typical formats would be 8N1, 8E1, or 8O1.
Normally, in 9-bit mode there's no parity used (9N1).