Here is a short test assembly code to check the bugs and the fix:

  LEX 'TEST' 
  ID #5C  
  MSG 0  
  POLL 0 
  ENTRY FNCT
  CHAR #F  
  KEY 'TST'  
  TOKEN 1
  ENDTXT

  NIBHEX 00
FNCT 
  GOTO LBL1  
  B=B+B A   * bug 1
  D0=AS 
  D1=AS     * bug 2
LBL1 
  C=0 W  
  P= 14  
  LCHEX 1  
  GOVLNG #0F216

  END


With a genuine Forth/assembler ROM, the result is
...
0012 00055           FNCT
0013 00055 6C00        GOTO LBL1
0014 00059 C5          B=B+B A   * bug 1
0015 0005B 138         D0=AS
0016 0005E 138         D1=AS     * bug 2

* duplicate label
0017 00061           LBL1
0018 00061 AF2         C=0 W
0019 00064 2E          P= 14
0020 00066 301         LCHEX 1
0021 00069 8D612F0     GOVLNG #0F216
0022 00070
0023 00070             END
...
 ERRORS : 001

showing the wrong D1=AS code (undetected), and the duplicate label error created by the bad B=B+B A opcode class.
	
With the fix, the two errors disappear.