So i just found out that some of the grad schools i applied to extended their deadlines to a month or to an indefinite time period ... is that a bad thing?

Maybe. No one really knows why they've extended the application period. Perhaps they haven't gotten too many applications yet? Or not the right ones? Only they would really know if it's a bad thing or not.

why don't you call the school and ask why they extended the deadline and if it's going to affect your admission in any way. that will probably be more reassuring than any of us