I think you're basically creating your own definitions to fit your argument.
Whether it's the Dogmeat item duplication glitch or the Dogmeat item duplication bug, patches are intended to fix both bugs and glitches.
The previous patches have addressed many bugs and glitches that were drastically affecting the game for many people. Overall, the quality of the patches for FO4 has actually been quite good.
Let's look at it this way - Patches are designed to fix bugs and glitches.
Intended game play mechanics do not qualify as bugs or glitches.
Bethesda removed the Dogmeat item duplication bug/glitch and the shipment duplication bug/glitch with patches.
Therefore these are glitches/bugs, and definitely not gameplay mechanics. If they'd put them there intentionally, I don't think they'd have removed them with patches.