I'm just getting my feet wet with the program but the way it is setup it seems like
Blue Iris can use BOTH which I find quite appealing. Under "trigger" you can tick off Blue Iris motion detection along with "Camera's digital input or motion" so that leads me to believe that both will be running. I do a little bit of programming myself and I'll always opt for having more data available in decision making logic than less. I'm not sure if Blue Iris does much with it other than trigger alarms with either/or/both but thought I'd check it out. Further, some of the software in cameras is becoming rather advanced with tons of analytics and I have at least one situation where I'd like to implement "object missing" analytics built into a camera. Not sure if I can with Blue Iris but I am hopeful since the developer doesn't disregard camera alerts wholesale as other software makers do.
In any case, if anyone has some ideas about these warnings in the log, any info would be appreciated.