What is the number in the right corner that appears some days...and some days not? e.g. 1st July +4, 2nd July +6 ...it isn't number of sport activities...as 1st july activity count is 3 and 2nd july it is 5... ciq.forums.garmin.com/.../1235799.png
A 43x78 thumbnail of what you see isn't the best way to convey information...
Anyway, it just means additional entries not represented by coloured bars in the cell for that particular day. Those entries are not necessarily timed activities.