I have chronic migraine so I take triptans frequently, they do not affect my baby. If you google each medication, the only one not advised is Naratriptan. The amounts in breastmilk are super minimal. It is likely just a coincidence
With rizatriptan you should wait a minimum of 4 hours after taking then pump and dump.
I was told by a doctor that you can take sumatriptan whilst breastfeeding and although it will pass through milk, it won’t be enough to have any effect on baby Not sure if rizatriptan is the same though xx