RLogin terminal output char 251 is somehow translated to U+00B9 in SyncTERM (all versions on Windows)

In v3.20, when connecting via RLogin with an unrecognized user name, I receive the following in SyncTERM for Windows (all versions):

      Synchronet BBS for Win32  Version 3.20  Copyright 2025 Rob Swindell
UNKNOWN USER: badusername
Starting new user registration ...
[√] HIT your BACKSPACE or DELETE-LEFT key:  

But with the new terminal abstraction in Synchronet, the following is displayed in SyncTERM for Windows (all versions):

      Synchronet BBS for Win32  Version 3.21  Copyright 2025 Rob Swindell
UNKNOWN USER: badusername
Starting new user registration ...
[¹] HIT your BACKSPACE or DELETE-LEFT key:  

I find this baffling as SyncTERM is only receiving and displaying CP437, but the char 251 (square root / checkmark) is being translated into a superscript '1' (U+00B9) - glyph that doesn't even exist in CP437.