Help timing scare

[1999Gst]

So I have a 1999 gsx with a 92 6 bolt swap motor roughly around 10,000 on it has hks 272s and mls head gasket and arp head studs, being powered bye a evo316g. Car has been running great for months.

Now here's the problem, went to take car out today and I always like to do a walk around check tires oil,coolent,timing belt, ect... But the problem today was that when pushed on timing belt rear can shaft gear(closest to firewall) had about a 1/4 inch of movement when pushing down on middle of timing belt to check tension ? Now in the past mOnths I've never seen it do this? And the belt seemed a little lose over the gear I could kind of slip it off almost of the gear ? Is this just because the car was off ? The cam gear closest to front end was still tight had no movement and no play in it? Should I start it? Or take it apart and look at the timing tensioner? I've never seen a 4g63 belt do this , thanks for advise and any help