Just happened the same with entry unit field. There's content module which has selector unit inside and another contend module. So to the inner content module only boolean values are passed fine to the entry unit's fields but not float or integer. I've found the similiar solution working: right after selector unit putting a script unit and pass values through it and then to inner content module but my entity has about 50 attributes, so should i write 50 in/outs in script unit? :(
EDIT: this problem doesn't happen when adding input collector parameters manually (not by wizard)
EDIT2: not really sure. Now it's happened with making input collector manually. I think it usually happens when input collector has more then one outgoing links (to several entry units, etc.). This solution seems to work: passing all the values through one noop unit next to input collector.