Some binary operations on DeferredSeries don't work

I get an error when trying to multiply two columns of a deferred dataframe:

ib.collect(df.A.mul(df.B))

TypeError: can't multiply sequence by non-int of type 'str' [while running '[35]: ComputedExpression[mul_Series_140480471782160]/[ComputedExpression[mul_Series_140480471782160]]:140480472023312/FlatMap(evaluate)/FlatMap(evaluate)']

Similarly, adding a scalar also doesn't work:

ib.collect(df.A.add(1))

TypeError: can only concatenate str (not "int") to str [while running '[39]: ComputedExpression[add_Series_140480422551952]/[ComputedExpression[get_column_Series_140480422552144], ComputedExpression[add_Series_140480422551952]]:140480472568336/FlatMap(evaluate)/FlatMap(evaluate)']

But adding two columns work.