Using Sophisticated Backpacks with a feeding module and putting a 'Mana in a Bottle' inside the backpack will cause the backpack to try and feed player the 'Mana in a bottle', the 'Mana in the bottle' will not lose any items and a new glass bottle will be put into your backpack. You can stack infinite bottles for free this way.

Are you on the latest version (0.4.34)? This should have been patched in 0.4.33.

I was able to reproduce this on 0.4.34 when the autofeeder is set to "Should feed immediately when hurt". Tracked here: P3pp3rF1y/SophisticatedBackpacks#693

Should be actually fixed in 1.0.0.