Label what the date belongs to
A record may show when an event happened, when someone wrote about it, when a copy was made and when an office filed it. These dates can all be accurate while referring to different stages. Before adding a date to your timeline, write the event it actually timestamps. Filed on Monday is not the same statement as happened on Monday, and a later copy does not necessarily imply a later original.
Worked example: the old photograph
A fictional photograph has an early date on its negative sleeve and a later stamp on the print. The later mark may identify reproduction for an exhibition. If you use it as the exposure date, you can create a false contradiction with the landscape shown. Compare the sleeve, sequence and accompanying notes before choosing which date belongs in the event timeline.
Apply it across the file
Use labels such as event, written, copied and filed in your own notes. When a source does not identify the role of a date, mark that ambiguity instead of silently choosing one. This prevents an apparent impossible sequence from forming out of unlike timestamps. It also leaves room for a real discrepancy to stand out: two independently supported dates for the same event deserve attention in a way that two dates for different document stages do not.