That is interesting. I was just about to post the same thing. I opened a PSB file in Affinity Photo and did not get the same colors from the HSL adjustment layer as in Photoshop. My idea was it had something to do with HSL vs. HSV (but I am absolutely no color space expert).
I already prepared a comparison between Affinity Photo 1.7.4.481 and Photoshop CS2 (both on Windows 7 64bit). The Affinity screen does not show the imported file, but I started from scratch in both programs to reproduce and understand the difference of the adjustment layers.
It might turn out useless, now that you are already aware of the problem, but here you go: