Here are the last 2 entries which I think relate to the test with and without the slash.
172.98.67.120 - - [18/Oct/2016:15:11:23 -0500] "GET /app1/ HTTP/1.1" 307 0 "-" "Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/53.0.2785.143 Safari/537.36"
172.98.67.120 - - [18/Oct/2016:15:11:23 -0500] "GET /api/4/ HTTP/1.1" 404 571 "-" "Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/53.0.2785.143 Safari/537.36"
172.98.67.120 - - [18/Oct/2016:15:11:23 -0500] "GET /app1/ HTTP/1.1" 307 0 "-" "Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/53.0.2785.143 Safari/537.36"
172.98.67.120 - - [18/Oct/2016:15:11:23 -0500] "GET /api/4/ HTTP/1.1" 404 571 "-" "Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/53.0.2785.143 Safari/537.36"