I have some questions regarding the application date of the patents. I use the "date" variable in the bulk file "application.tsv", but I found some of the dates are hard to interpret. Some examples are patent_id = 4255928, date = 9178-12-11; patent_id = 3963197, date = 1074-08-14. Besides, I checked the grant date for these patents, and they are all well defined. May I ask what was going on here? Does it mean those patents are missing in the application date or is there something I can do to recover their application date? Thanks very much!