This issue is solved if prior to Step 3 the following command is run in rdb:
adapter.move_cursor 1
However, adapter.cursor_pos is then 7. See allowing non-existent indices

from quill.

This issue is broken again if:
Step 1 above.
Step 2 above.
Step 3 above.
Step 4: adapter.move_cursor 1
Step 5: adapter.move_cursor 0 // Without this line, issue is solved
Step 6: (adapter.type_text "abcdef").class // Yields String.

This issue is fixed with a non-zero cursor_pos.

After fixing the allowing non-existent indices issue, the step 4 listed here does not fix it.
HOWEVER, forcefully setting cursor_pos to a non-zero index (even if it does not exist) fixes the issue.

from quill.

Fixed in one of the commits to fuzzer branch on April 30th.

from quill.