A few issues and notes

Sometimes the autosave logo appears, but no autosave occurs. This mostly happens during the start or end of a cut-away scene.

Autosaves triggered by collecting or looting objects or completing some sequence don't save everything. If Lara get's killed or reload checkpoint is done, some XP and some loot may be lost. Worst case is just after a battle and Lara looting the soldiers. There's an autosave for each soldier looted, but if a reload occurs, the loot is lost and if all the soldiers in a sequence were killed, then they're lost also. If only some soldiers were killed, they may respawn from a reload checkpoint. Ammunition usually gets restored from a "partial" autosave.

Autosaves by using and exiting a camp appear to be full saves.

Autosaves triggered by crossing some key position on the map also appear to be full saves. These also restore Lara's position to the trigger position if a reload checkpoint is done. Sometimes the position based autosaves appear to be one time triggers, but usually if you go back to a prior trigger point or a camp and then cross that position again, another position based autosave will occur.