I have this issue as well. It seemed to have gotten worse with the released 3.5 version. I've had almost all of my testcase duplicated within a given suite. I've been updating existing tescases recently and have renamed a few, but that's not typically the case with these testcases.
It seems that SoapUI's interpretation of spaces in a testcase name is inconsistent.
File system shows:
Valid-set-and-get-values-null---all-values%2C-lock-and-inherit-mixture.xml
Valid-set-and-get-values-null--all-values-lock-and-inherit-mixture.xml
SoapUI shows same testcase twice:
Valid set and get values null - all values, lock and inherit mixture
Valid set and get values null - all values, lock and inherit mixture
If spaces in testcases is problematic, maybe the should be disallowed? Is there a workaround for this? Due to this and another issue I'm having with 3.5, I'm thinking I should go back to 3.0.1 for the time being as I'm losing a bit of time over these issues.
Thanks,
Mary