Before we start, this actually already happened before the weight conversation feature introduced (probably could trace back to 3.62 or earlier) and I think it is not really related to the latest update.
So here's the weird weight penalty I noticed: I got 4 pieces of armor, weighted 1.4kg, 2.3kg, 10.4kg and 13.6kg respectively.
If I wear the armors in the following sequence: 1.4 + 2.3 + 10.4 + 13.6, the total weight shown in the right panel is 27.9kg (btw this is wrong and should be 27.7kg?), and more importantly, the weight penalty would be
7%.
However, if I wear the armors in the following sequence: 13.6 + 10.4 + 2.3 + 1.4, the total weight remained unchanged (27.9kg) BUT the weight penalty is
8%My character has a weight of 60kg. In-game photos attached and if save is needed, I can provide it anytime