Premiere Pro V23.1 -3dB audio drop on export

We're working with R128 compliant audio and have found that when adding media to a sequence, the audio is 3dB lower.

We work with video files containing multichannel audio to supply to our international clients. Therefore we configure a 22 channel output with the sequence channels routed 1 - 1, 2 - 2, 3 - 3 and so on. With premiere only offering stereo bus', we have to route each track to a stereo pair, for example, routing track 1 to output 1 & 2 and then pan to the left, therefore routing track 1 to output 1.

In the below example, I'm only including a stereo split to show the drop in volume.

Original media reference tone in player at -18dB

Original media in the sequence, reference tone at -21.2dB

Same reference tone exported and reimported playing at -24.2dB