If the pump performed well, maybe a thorough teardown, de-greasing, and re-lube would keep those contaminants from re-occurring? Could have been a preservative inside the hose, pump body, check valve, etc.
I agree with you though if it seems the pump design is at fault. In that case no precaution would help, aside from a quality means of particle filtration between the pump outlet and your AT44 inlet.An inline sintered bronze filter might be a cheap and effective recourse.
Ed