Your jacket is made out of Hyvent, which isn’t the most breathable fabric in the world.
However, breathability is a marketing con that basically says “We’re great, we can defy the laws of physics”. The idea is that water vapour wants to move from an area of high concentration, to an area of low concentration across the membrane you’re jacket is made from to attempt to reach an equilibrium. The obvious problem is that generally, when it’s raining, the air outside your jacket will have a higher concentration of water vapour than the inside of your jacket, and water vapour won’t be that interested in moving outside. The DWR helps by stopping water pooling on and wetting out one side of the membrane to help “lower” the apparent concentration immediately outside the membrane and encourage vapour to move across, once it’s gone and the jacket starts to wet out, you’ve compromised the breathability significantly. So actually, “breathable” waterproofs don’t actually work that well in rain.
I’d think that what’s happening is that once the water vapour from your your nice and warm soft shelled body shifts into the cavity between the waterproof and it, there’s no incentive for it to move across the membrane and out into the outside world. Additionally as it finds the colder inner surface of your colder waterproof, it’s condensing back into liquid water, which is then being rubbed onto the outer fabric of the softshell and making it wet.