My crystal ball doesn't show up any solution, so some more input is required: Is the chip still working (test with an additional output), does the I2C hang (skope) or does the PC application hang?
Is the chip still working Yes.
does the I2C hang No. SDA and SCL is high.
does the PC application hang? Yes. The name of the PC-Application is EZ-Click. As i said.
Even if the chip is not working or I2C hang, EZ-Click should not crash.
When you can prove that the crash of the EZ-Click program happens on different PCs I would suggest you to file a technical case, giving Cypress the same information.
BTW: When both I2C-lines remain high this will not prove that it does not "hang", it only proves that there is no communication taking place.