I've been looking into all of the ins and outs of Metz flashes in relation to my Mamiya 645 AFD, and I finally came across something that explains a lot about them. For your particular unit, the 70-5, the proper adapter is the 3xx2 series, not the 3xx1. I don't know which camera this is for as not all adapters are listed, and some, as is my Mamiya, the adapters were made by the camera manufacturer rather than Metz. I have the Metz 54 MZ4i flash, an SCA 3002 type, and the 3951 adapter, an SCA 3000 type. First off, the adapter had to be forced on as the older adapters do not fit properly on the newer flashes, but they do work the other way around. Second, while I seem to get TTL functionality with it, none of the other functions listed in the Mamiya manual work so I don't get a flash icon in the viewfinder and the flash doesn't automatically set ISO. Not an insurmountable problem.
According to the guide, these "programmable" adapters, the 3xx2 series, lost that function when the only person at Metz with any knowledge of it died. And then they went bankrupt so that was that. In the meantime I'm still looking for the proper 3952 adapter for my camera, that's assuming I can get the other one off the flash as I really jammed it in there. Reality too is that I never liked flashes, nor do the subjects in this day and age of iPhone photos without them and digital sensors of ISO 12800 and more. I've tried low light shooting without one on my Mamiya with pushed film with pretty mediocre results.
How this helps with your problem of strobing is this, with the wrong adapter the flash isn't working properly, without it it works properly. There is no mention of a 3802 adapter in the document below nor a 3801, so probably the camera manufacturer supplied it. What camera is it?
Metz SCA guide in German (I used Firefox translate on it myself, but whatever works for you.)