Sentence:  To interpret , indeed , the era from 1000 to 800 as a period mainly of consolidation may be a necessary but unfortunate <WSD>defect</WSD> born of our lack of detailed information ; if we could see more deeply , we probably would find many side issues and wrong turnings which came to an end within the period . 
Meaning of the word marked with <WSD> tags:  a failing or deficiency