Thank you Emilie for your very prompt and useful reply.
Please find a photo of the module below. For now, I have swapped out with my other plaits, which hopefully will eliminate, or not either/both an issue with the power cable / psu. As I’m sure you understand, the intermittent nature makes this a matter of waiting and seeing to some extent. Also, this is complicated by the fact that I am patched and ready for a show tomorrow, so working on the case is fiddly at the moment. Its a doepfer 9u monster, full, and heavily patched.
It is possible also that the psu on one side of the case is the issue. On these cases, left side is one psu, right side another and the placement of the two plaits modules happens to be such that they are not on the same psu.
Happily, the “spare” plaits is not in use for this patch, and needing a little more mixing control anyway, I have taken out the affected plaits, swapped in the spare one, using the same power cable, and in the space left behind that, my veils has gone in.
If I can cycle power 4/5 times without issue, I would strongly suspect a problem with the module. If the problem persists, I will swap the power cable. So far I have power cycled twice with no problem ( but don’t want to switch on and off and on and off needlessly, too much)
Many thanks again for your time and attention to this, it’s much appreciated!