There are two issues observed regarding displaying graphs for trapper items with no or old data.

(A) Suppose we create a trapper item, but do not send any data yet. View a simple graph for that item and click on "All". Observe a negative number of months and days:

(B) Suppose we create a trapper item and send some old data, say, from 2002. View a simple graph for that item and click on "All". Observe that we can now move the slider to 19th century and note how all graph labels are the same.