Is it common practice for an admissions office to ask a transfer student for the current semester's grades? I applied to a state university for the Fall semester the first day that applications opened for transfer students.
The admission office wrote that decisions take 8-10 weeks.
After 10 weeks, I emailed the admissions office and they told me they would have an answer in an additional 2 weeks (for a total of 14 weeks from the initial submission date).
Today, 14 weeks after my submission, I emailed them and asked if they had any update since I would have to make living arrangements if I got accepted.

They responded: 


  The admission committee reviewed your application and determined we
  need your spring grades. We will review your application once we get
  an updated transcript in May or June. Due to limited space
  availability, it would be helpful to have a back up plan for the fall.


Is it common practice to give students responses in such uncertain terms?
I responded asking if there was anything I can do to speed up the answer (e.g. giving them my current grades) but didn't receive a reply.

I'm not sure that this is relevant, but my GPA is 3.86 (which makes me wonder why they would need to see my grades).
It's not so weird.  A lot of places do admissions the week before classes start, or even after classes start.  Only selective universities plan many months ahead.