Can you APOP (rock, feed etc) to get her back to sleep at 5am?
I think probably looking at your routine this is most likely an UT issue. If her naps are 1h15 to 1h25 those are UT naps and she is trying to tell you she needs more A time. At the moment she is getting nearly 3h day sleep and a less than 12h day, and not always getting a full 3h A time. I know it will not entirely be in your control, but I think at a minimum she needs 3h A time consistently and a 12h day. If you are getting naps less than 1h30, increase her A time by 10 mins and hold for 3-4 days to see the effect. If you get a short nap, I would actually just go for a slightly early bedtime rather than a 3rd nap (unless they are all short) as often a late nap can cause UT at BT at this age, and encourage the EWs.