In which codebase did you find this error? Did it occur on the intended platform, or on porting it to something else, eg, code meant for ARM being run on something with a 16-bit int?
As explained earlier, the occasional packet will trigger the preamble detector despite mismatching sync words. It’s just a crude filter to damp down the volume of extraneous stuff, both keeping it off the backhaul and keeping the pool of demodulator engines in the chip available for signals more likely to be relevant.
Overall you’re leaving more unsaid about what you’re trying to do than you’re saying. Presumably that is intentional, but it makes for an odd read.