Yes, something seems to be wrong. Difficult to tell what, can you share the projects, Bootloader and Bootloadable? Use Creator -> File-> Create workspace bundle (minimal) and upload the resulting .zip.
from time to time I get a spurious interrupt and execution gets stuck in the Cm3Start.c::CY_ISR(IntDefaultHandler) This is mostly caused by a clobbered stack or bad pointer handling leading to accessing non-existing memory etc.
Thank you for your reply. I'll try to create a simpler project that exhibits this behavior (my app is pretty complex) and post the project so that yo can take a look.
It will take few days until then, I have to finish something else meanwhile.