Yeah, Having now cut through the original plug’s plastic layers (to see exactly what wires went where as continuity was clearly failing) I can say it’s pretty weak in terms of support.
I just got a cheap 4-pin down the road as I didn’t want to wait for delivery but, once I finish this project, I may decide to lose another few cm of flex and go for something even more solid like this which has a crimping cable support.
Quite why Waldorf opted for this sort of connection is beyond me!