This full featured (!) BASIC VER 1.0 keeps track of the column and inserts CRLFs after column 70 or so. Even though the expression printing routine is sending NULLS now, the column is still incrementing.
A little further down in the code is a candidate instruction to modify. At $03E6 there’s a CPI 46. It looks like this is testing to see if column 70 has been reached.
My patch was to change 46 to FF. This is a 255 column terminal now!