This is a classic thing with Industry, they qualify a process that is working and shows good performance, but this process needs to be changed for reason XYZ, often because it is maybe a bit too expensive or doesn't align with the rest of their processes. The small change in the process wasn't that small and takes a little while to be identified because by the time you catch it you might be further down the line and this would be caught by a QA process and not a QC process, that might have deemed at that point not necessary because you had no reason to fault the part.
The second part is that some things are rated and verified but not tested extensively, since you might have prototype you might misdiagnose a failure of a component for a behaviour of your prototype, when in fact you had a deeper problem, but timelines with the added fact that so far you didn't think about that problem because it shouldn't have been a problem can catch you really off guard. This is usually where people testing the same thing in an exotic environment can ring alarm bells for others and that often happens at conferences...
People often under estimate how much you can get bitten in the back by such little details that become huge details.
Depending on the electronics and where the MOSFETS are, I would be them I would probably trash the electronics, take the spare that they had, validate components that get in and rebuild a control box and re-integrate it, provided that this is doable. It's expensive but provided that you have no choice that gives you a backup system that you can test code on before pushing it on the actual probe and might help for problem solving by being able to do measurements and test on the actual setup... Provided that they have the time and resources. Otherwise I wouldn't YOLO it given the fact that it might just straight up not work at the moment you need it the most and a little delay is better than nothing and they can spend the time re-checking part of the design that might also be weaker...
But heh, who am I but a random guy on the internet...
They found it was cured by lemon juice, but they didn't understand the details. Over years, they switched to lime juice (less vitamin C), put it in copper pipes (leaches vitamin C). But ships were faster so there was more fresh food available, masking the problem. Then scurvy starts mysteriously popping up again 100 years after it was first "cured."
Hard to keep track of the effects of all the details in the face of various co-dependent things changing simultaneously. Recipe for surprises.
This is a classic thing with Industry, they qualify a process that is working and shows good performance, but this process needs to be changed for reason XYZ, often because it is maybe a bit too expensive or doesn't align with the rest of their processes. The small change in the process wasn't that small and takes a little while to be identified because by the time you catch it you might be further down the line and this would be caught by a QA process and not a QC process, that might have deemed at that point not necessary because you had no reason to fault the part.
The second part is that some things are rated and verified but not tested extensively, since you might have prototype you might misdiagnose a failure of a component for a behaviour of your prototype, when in fact you had a deeper problem, but timelines with the added fact that so far you didn't think about that problem because it shouldn't have been a problem can catch you really off guard. This is usually where people testing the same thing in an exotic environment can ring alarm bells for others and that often happens at conferences...
People often under estimate how much you can get bitten in the back by such little details that become huge details.
Depending on the electronics and where the MOSFETS are, I would be them I would probably trash the electronics, take the spare that they had, validate components that get in and rebuild a control box and re-integrate it, provided that this is doable. It's expensive but provided that you have no choice that gives you a backup system that you can test code on before pushing it on the actual probe and might help for problem solving by being able to do measurements and test on the actual setup... Provided that they have the time and resources. Otherwise I wouldn't YOLO it given the fact that it might just straight up not work at the moment you need it the most and a little delay is better than nothing and they can spend the time re-checking part of the design that might also be weaker...
But heh, who am I but a random guy on the internet...