Canvas bags stack. You can put items inside close separate the stack. And dupe the items

Much better explained and in video form here: AllTheMods/ATM-4#13

Forge and Minecraft version

1.14.4 Forge 28.1.20

Bluepower version and build number

0.3.123 alpha

Thanks for reporting, fixed in bluepower-1.14.4-0.3.125