By adding the extra WRITE commands, you are probably writing a BYTE value now instead of only a WORD, which will make the error go away as described above.

The crossing code boundary issue has been discussed many times here on the forum.

In Microcode Studio, go to View > Editor Options > General Tab
Check the Disable 'code crosses boundary' ASM warning checkbox.
If you are using the BRANCH statement, change it to BRANCHL.