Can you share details on how you are applying the claymore straps?
You can not apply claymore straps in phoenix directly (yet?). Use amdmemtweak. You can read current staps for AMD cards when running claymore with this tool and then apply it before starting phoenix.
When you apply straps on AMDMemTweak, does it set the same value for
all frequency straps? When it reads the straps, it reads from the current frequency state which may be different when running idle or half load, but when you set something using AMDMemTweak, I'm guessing it needs to make the straps the same for all frequencies. Is this the case?