I'm glad I am not the only person having this problem.
Mine is on a basic Ryobi (probably very similar to your Delta)
I first noticed it after I had to replace the tire on the lower wheel - was afraid I had messed something up.
I found the following chart:
http://www.bandsawblade.com/chart.htm
It indicates that blade tension and tooth set (both mentioned in posts here) are two likely culprits two issues.
I'm glad that tightening the tension solved your problem
It hasn't helped me yet
With the tension set until the spring is almost fully compressed (a no-no) I am still having the problem.
Given that this was a display model -- and had probably sat unused but under tension for MONTHS -- is it likely that the spring itself could stand replacing?
Or is the blade (1/8th") a more likely culprit?