LTC3106 - getting 3.26v instead of 3.3v
3.26V is within specification for the device.

Device manufacturers can only guarantee output voltages to be with a couple of percent. 3.26V is within ~1.5%.

Also as others have commented how accurate is your voltmeter?

It could be anywhere between 3.22 and 3.40V at 25°C.

What is the input supply voltage?