The FD adjustment is most likely, especially since it started with the cable replacement.
When you stand and pedal hard the tops of the rings flex outward. So if the FD trim is a bit inboard, it might be OK on the stand or when pedlaing lightly, but will cause a shift when the rings move out (same as if the FD moved in). If you have an inline adjuster, trim the FD outboard a bit more and it should (hopefully) resolve.
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