Of course it is... there is RX 5500 with all disabled CUs in the same SA... one SA with 14CUs and the other with 1
There is no point in use redundant CUs to increase yields if only these with 1 CU defect in each SA fits.
PS5 will probably have units with the 10, 10, 10 and 6 CUs per SA.
Edit - Fixed the 20 lol
If that is the case they may go with 40/56 CUs and not 36/52 CUs.
They are trying to increase yields using chips up to random 4 defectives CUs.
Any chip with 5 or more defective CUs go to recycle.
That's not how RDNA works. Sony and MS don't disable 4 CUs for yields, 1 or 2 CUs are actually enough in order to get almost the exact same yields considering the extreme limitations 4 specific CUs will have to follow (more on that at the end), but they have to disable 4 CUs even if all they will ever need is just to disable 1 CU, because their GPU has 2 SEs.
In RDNA you don't disable a single CU, you disable a full WPG and a WGP contains 2 CUs. If your GPU also has more than 1 SE, you have to keep the WGP count in each of them the same. So if you disable a WGP in one SE, you have to disable one WGP in the other SE.
If one CU is defective, just a single one, you have to disable the WGP that contains it, right off the bat, you've disabled two CUs. Then, because you've disabled a WGP in one SE, you have to disable one WGP in each of the other SEs. Because PS5 and XSX both have 2 SEs, if they want to disable a single CU, they have to disable a full WGP and another WGP in the other SE. That's why you will never have a PS5 with 4 disabled CUs in the same SA - Because the SA is inside the SE and if you have one disabled WGP in that SA, the second WGP you disable must be in the other SE. So a GPU with 4 defective CUs in the same SA goes to the trash bin.
Now that we've laid out the rules, just think how little PS5 GPUs will actually have 4 defective CUs:
0 defective CUs - 100% of these cases will become a PS5 GPU (obviously).
1 defective CUs - 100% of these cases will become a PS5 GPU (because you can disable that WGP and another random WGP in the other SE).
2 defective CUs - 53.8% of these cases will become a PS5 GPU (the second defective CU has to be in the other SE (51.28%, 20 our of 39), or in the WGP you've just disabled (2.56%,1 out of 39) and you just disable another WGP randomly in the other SE).
3 defective CUs - 4.04% of these cases will become a PS5 GPU (the previous rules apply and on top of them the third CU has to be in one of the two already disabled WGPs (5.26%, 2 out of 38), or if the first two are already in the same WGP, then it has to be in the other SE (52.63%. 20 out of 38))
4 defective CUs - 0.11% of these cases will become a PS5 GPU (the previous rules apply and on top of them the fourth CU has to be in the WGP that already has 1 disabled CU (2.7%, 1 out of 37))
That means that only 1 out of ~25 APUs that come out of the fab with 3 defective CUs will actually become a PS5 APU and only 1 out of ~1000 APUs with 4 defective CUs become a PS5. So as you can see, disabling the third and fourth CUs does little in terms of improving yields, I'm sure that if Sony and MS could have had 38 CUs (10.85TF) and 54CU (12.62TF) active, they would have gladly done so.