The issue here is “variant characters” (“bracket characters”  of the Open Systems IBM-1047 view displaying as Y, of the US/Can IBM-037 View)
Short answer: The FTP translation tables are “customizable”.
See attached document page 1048 but the same principle
In this case IBM-1047 is probably the mainframe code page that would resolve this issue.
Some Developers use this code page for better support of the bracket characters  in the emulator because they code in C/C++ almost exclusively.
They set the C/C++ compile to read files encoded with IBM-1047 to accomplish this, so a lot of their program source is stored on the mainframe in this encoding.
Then the next issue will be whether the mainframe terminal emulation program (Extra, Hummingbird or Personal Communications) can display the characters correctly.
That is an emulator issue, not a code page translation issue.
Also, please see an explanation of the 13 “variant characters” that cause problems during ASCII <-> EBCDIC conversion – starting on page 1047.