In the K22 mask sets 0N50M, 0N51M, 1N41K, and 0N74K (and possibly more, these were all I looked at) there is an errata e6939 which has the description "Core: Interrupted loads to SP can cause erroneous behavior". To summarize the errata as I understand it, if an instruction of the form "LDR SP, xxx" is interrupted bad things may occur.
The workaround is to not use instructions of that form. Okay, fair enough I guess, if writing assembly code. But what is the workaround for C code, since I can't control what the compiler emits? I would appreciate if someone who is using a K22 part can share how you are ensuring that you don't encounter this errata.